Although haste may have the highest HPS value of all out secondary stats, there still is a point where its value is diminished, due to the fixed cooldown on Holy Shock. Since Holy Shock is our most reliable and efficient source of gaining HP now we will want to be casting it on every cooldown.

Unless we completely ignore casting Holy Shock (I'm not saying this is effective at all) haste will have a plateau-ing values, and should be considered as such.

Did some quick math in an excel spreadsheet to find this "plateau":

NewCastTime = BaseCastTime * ( ( 1 + HasteRating / ( RatingConversion * 100 ) ) ^ -1 )

A haste rating value of 1494 would put the GCD at 1.384615 seconds, and HL/DL at 2.307692 seconds. This would allow you to Holy Shock, put in two HLs or DLs and then holy shock again (total time taken of 6.000000 seconds).

This doesn't include calculation of haste effects, anyone know how to incorporate that in?

Will edit new calculations in if I figure this out before someone else does.

PS. Haste rating will always benefit the ticking speed of HR, so it wouldn't be a hard cap, just a soft cap.

Edit: As far as I discovered, haste effects are simply applied after haste rating (CastTimewithHaste * (1+Percentincrease))

From that, here are the haste values (assuming 9% JotP, 3% SoL, 5% raid buff) you need to fit different combos of GCD spells and HLs/DLs in between your holy shocks:

HS + 2 DLs: 0 rating
HS + 2 GCDs + 1 DL: 0 rating
HS + 1 GCD + 2 DLs: 2350 rating

HS + 3 DLs seems to be impossible, at a rating of ~4875

Each haste plateau also increases the HPS and HPM of HR as well.

The haste plateaus are not someting simple like "When the cast time of HS+2HL reaches x seconds, do this". With our basic haste from talents HS + 3HL is already better then HS+2HL. The only time it is not, is when you add an additional spell in the rotation, such as a LoD/WoG/Judgment/HR. There even exists a haste rating where using Holy Shock is a reduction in HPS and HPM, but this haste value is too high for standard gear based haste to reach, only under haste cooldown situations.

I'm also of the feeling that at this moment in time crit is highly undervalued and haste overvalued due to paper statistics on HPM/HPS.

I've rarely found myself in a situation whereby someone could have been saved due to haste. Wrath was slightly different as we spent a high proportion of our time focused on 1 or 2 spells without much utility, but now things have changed and our proportion of instant cast heals nearly outweigh our cast timed heals. Furthermore at this moment in time in I simply can't afford to spam casting spells. For that reason I find haste more of a luxury that will probably be more beneficial later on for fine tuning. Right now, hate on me all you like, I'm reforging haste for crit.

I have found myself getting frustrated that people have over twice the HP and I am hitting similar HPS that I was in Wrath. More importantly I really value and appreciate crits, because more often than not they'll save me mana. Crits served relatively no purpose in wrath due to overhealing, but that's certainly not happening to me anymore. Healing is so much more cautious and calculated, and really doesn't feel like the light bombing it used to be. So why haste? Not to mention holy shock crits, Power Infusion is a beautiful fight changing proc. Give me heavy raid damage while I'm sitting on 3HP and a power infusion proc ticking down and I'll not break a sweat!

If you look around, you can see some parses from raids. They tend to be pretty varied right now, but it is fairly safe to assume that Holy Radiance will be around 20-40 % of our healing on AoE fights. It is also fairly safe to assume that protector of the innocent will be at least 20% as well. The contribution from our normal heals will be only around 20% as well, with beacon and others filling the rest.

As per the OP, holy radiance gains 10% efficiency per 10% haste. 10% haste is about 7.14% crit. If holy radiance is 30% of your healing, 10% haste would be a 3% increase in efficiency from just Holy Radiance. The crit on the other hand would increase your total efficiency of all spells by about 3.57%. Then consider that haste would give a 10% gain to HPS for all spells, while crit would give 3.57%. Then consider the Protector of the innocent implications. 10 man will see less powerful Holy Radiance, so it is not always so clear.

The only thing going against Haste is that GoAK only lasts for 5 heals.

I've experimented with this and don't feel comfortable with it.

Like you, I'm still running 5-man dungeons, almost all random. Perhaps in a more predictable environment (like a guild run with knowledgeable players) I would employ this but the lack of experienced players has almost made it necessary for me to keep a constant stream of heals on the tank. Then again if everyone knows what they're doing, why even bother? Chock that under personal preference I suppose. For me, I like to keep things as simple as possible.

I like the double heal effect Beacon offers when targeting the tank, I often will go OOM on some pulls (mostly due to ignorant players) and like having the insurance of A.) Tank is getting healed, regardless of what its for. and B.) If I need a targeted heal to count, I know it will have a little extra on top. This method makes the most sense to me, it's something I'm comfortable with and most importantly, it's working.

I feel this ties into what others have mentioned, how crit is still sort of up for debate as far as its priority. I will say that due to the OOM issues I'm having (which are rightfully not so much game related but really me learning), I'm finding Spirit to be my most reliable stat. This consistently saves me, and keeps me going the last 15% of a boss fight. Once I acquire better gear, and a solid rotation, I'm sure I'll round out my crit and haste in exchange for it.

Here's a log from our Magmaw 25 kill this week to back this up:

World of Logs - Real Time Raid Analysis

After poking around on there, I feel fairly comfortable saying that mastery is certainly a much weaker stat than haste in most of the common raiding situations. So far, Mastery is near-useless compared to haste on Magmaw, Chimaeron, Omnitron, Halfus, and Valion/Therona. If I were to prioritize mastery, I would be sacrificing around 6% haste for roughly 2,000 HP shields on Divine Light targets. I can't see any evidence that the beacon target is also affected by a shield, so it really does seem like almost a waste, since most of my shields will be significantly smaller.

In addition, I was able to comfortable CS 17 times that fight and still end up on top of the charts (this is post-nerf). Crusader strike is an extremely cheap, reliable way to generate HP and potentially regain mana as well. In my experience, a majority of the fights so far tend to be periods of high damage or "emergency" healing, with long phases of light healing to encourage regeneration. This may change in heroics, but I see no reason not to take advantage of those phases with a few CS hits.

Compare it to beacon-swapping, and it's significantly more mana-efficient with the same (better, because you can still heal a non-beacon target with HL and take advantage of beacon) results.

Played properly, we're still by far the most mana-efficient healing class in the game, and we need to be taking advantage of that.

The reason crit is a bad healer stat is it is completely random. Yes, it procs IoL, but would the tank have been better off having a 30% chance to get the right sized critcial heals, or getting ALL his heals .1 seconds faster? If you are stacking crit, unless you can guarantee 100% crit, you are leaving your healing up to chance. If you're keeping Conviction up, you have enough crit. Also, last time I ran parses, mastery actually out values crit by a long shot.

In this expansion, to me, crit has moved from chance to utility, and I think that's the point I'm trying to make. I don't use my crits on the basis of hopefully they'll keep the tank alive, rather, if I get a proc or a crit heal that gives me assurance or saves me mana throughout an encounter then it's good. A crit on DL for example is almost the value of 2 normal DLs, sure the crit happening is based on chance but if/when it does happen that's an extra heal I don't need to cast and thus mana saved. Whereas in Wrath that would be an overheal and completely redundant/lost, a 40k crit on a health pool of 140k matters.

I realise for theory this is hard to evaluate, which is why I said on paper haste seems a better stat. I'm going to try stacking haste over crit for a while and see how it compares anyway, but I just feel with the pace healing has at the moment crits give you the utility to decide as opposed to giving you a statistically false sense of assurance like they used to.

All in all hPala to me has become less about spamming and more about making choices, and I think that carries across the board in healing. I just feel that at present crit supports that mentality more than haste does, because healing doesn't feel like a sustained action but rather small burst reactions right now. I'm not going to judge without knowing though, which is why I'll switch haste and see how it works in practise for me.

Haste increases your mana regen as well. More haste, faster swing speed. More SoI mana. The fact is you dont want to be leaving your healing up to chance. Not up to procs OR hoping the crit saves them. Haste gives a constant benefit that is quantifiable, measurable, and reliable. Crit is none of those things. Maybe one night you crit 20% at 35% crit chance, the next night you crit 50%. Well your gear is crit dependent, so if you get some bad RNG, your healing is now down the tube for the night.