It should be a code copy of the current Scourge Strike. Since the initial attack already passes certain roll checks (Hit, Expertise) and benefits from certain stats (Crit, Haste), the secondary hit already innately passes/benefits. The only thing that should specifically influence the secondary strikes damage is Inquisition (and other Holy based mechanics). General damage modifiers, like Avenging Wrath, should not effect the secondary strike because it increased the damage on the initial strike.

Furthermore, the secondary strike should be based on actual damage done, IE after damage reductions such as armor and various cooldowns/procs.

TV hits Target A for X
Hand of Light hits Target A for X*Mastery%*(1+Inquisition)

This means this trinket will much less annoying, as well.

These changes are definitely making me salivate enough to forgive Blizzard for forcing me to completely rethink my gearing strategy.

The new mastery should easily push TV to first priority since it was pretty close already. If its doing 270% WD up from 235% as someone mentioned, then it should be head-and-shoulders above HoW/Exo. CS will close the gap for similar reasons, but its damage should still be 4th. It will be interesting to see if this puts it ahead of HoW/CS in priority, though. Since the damage gap will narrow and the extra HP from a CS will result in more TV damage it may push ahead on the priority list (prioritizing CS also helps a bit to fill more GCDs which could work in its favor as well).

If this ends up being the case, then it simplifies our rotation a bit with a relatively static CS +2xFiller, repeat (compared to the CS +2 or more fillers based on Exo/HoL procs after the first 2 fillers). It will still occasionally happen that we get a DP (nee HoL) proc right before our 3rd CS and then get a 2nd proc on the TV following the CS. This would lead to a string of 3+ TVs before the next CS, but there's only a 2.25% chance of that happening (about once every 10 minutes).

If CS *doesn't* move ahead of HoW/Exo, then our rotation would seem to get *more* complicated. The priority would be something like TV/Inq > HoW/Exo > CS > other stuff, but if you have a DP proc to burn, but CS is also available and would be your next ability after, then it would be better to use the CS first and the proc after (CS TV instead of TV CS does the same damage, doesn't risk missing a proc, and gets CS off cooldown sooner). What happens if other things besides CS and the DP proc are available, though, is anyone's guess at this point.

4 swings in 9 seconds means you have a 2.25 hasted swing speed. That's either a terrible weapon or quite a bit over "negligible" haste. 3 swings over 9 seconds seems a lot more reasonable to me (3.6 / 1.09 / 1.10 ~= 3.0). This drops the total HP generated to 4.6 in the first case. Still more than the "after" value, but only a ~17% drop.

However, this simple analysis is glossing over a couple key issues. First, its not uncommon under the current system for DP procs to be wasted. Any proc under Zealotry (~17% of our dps time) is automatically wasted. In addition, even small strings of Exo/HoL TVs we get at full HP will end up wasting some procs. Under the new system I see no reason why DP procs would ever be wasted. Second, its not that uncommon for a CS to get pushed back to fit 3+ fillers if Exo/HoL/3 HP happen after using 2 fillers, but this may not be desirable under the new system.

This set of changes seems to be a nail in the coffin for 3s CS. You need nearly 4k haste rating to hit that cap which means you need to find gear with ~8k total ratings on it (since the best you can generally do is get about half of an item's rating budget into a particular stat). My current avg ilvl 354 gear has 5356 total ratings (including useless stuff like dodge/parry/resil from gear), so we're still well below the point where this would have been a reality to being with.

Now that mastery seems to be easily the best secondary stat, we'll want to dump as much as possible into it. In order to meet the haste, hit, and exp caps with the remaining 50% of overall item budget, we'd need ~5420 rating points for them which means nearly 11k total rating points. Going from ilvl 200 Naxx gear to 277 ICC stuff was roughly a 2x increase in combat ratings on gear, so its possible we could hit this in late Cata, but its certainly not something we'd have a shot at any time soon with mastery stacking.

It may be worth doing a sanity check, though, to make sure that increased CS/TV damage hasn't boosted the value of a 3.0 CS (and hence haste) to a value that competes with the new mastery.

New strength/3% crit damage meta gem in next patch:
Ptr missing an important change - Forums - World of Warcraft

It is 20%, or close to it- I was getting (on average) an extra 19.3455% of the Templar's Verdict, Crusader Strike, or Divine Storm damage as Holy.

Hand of Light damage is equal to Damage Dealt * (1 + %Mastery). From the tests preformed, it cannot proc on its own, but if the TV/CS/DS crits, HoL will do more damage accordingly to total around 20% (assuming no Mastery on gear).

Because the PTR is still not flagged for Cataclysm, tests with Inquisition cannot be preformed.
Additionally, I am not sure if Hand of Light will additional damage to targets afflicted with Curse of Elements type effects, but I would assume it would do so.

Finally, it is possible that Hand of Light could suffer from partial resists, as seen from my data not being equal to exactly 20% of the time- I will re-post in a few minutes with findings.

EDIT: The current PTRs are currently offline (for maintenance ?).

From the updated patch notes on mmo-champion.com:

Not so important for ret (but really nice for prot and situationally for holy I suppose), but...

We get a cool new talent! It doesn't effect dps directly, but survivability is a big part of most of the new raid encounters, so this should be pretty useful (and cause a lot of PvP QQ I'm sure).

If Crusader Stirke is going back up in value, does this mean we will want to get the cooldown as close to 3 seconds as possible again? With the additional benefit to Templars Verdict, our rotation may change back to CS, 1 Filler, CS as optimum dps. As such will our best secondary stat be Haste or Mastery?

Overall, I think it is a shift in the right direction and probably should have been our Mastery from the beginning. Looking forward to the changes.

simc's scale factors are expressed in dps gained... The 359 ret profile (odds are it's far from optimal, I haven't spent a lot of time on it) has these rough dps gains:
1str: 2.3
1exp: 1.3
1hit: 1.9
1crit: 0.9
1haste: 0.8
1mastery: 0.4

I'll try to get the PTR changes implemented over the weekend.

I believe the poor scaling of ratings (due to secondary stat budget on items being relatively low, considering very low rating scaling coefficients for level 85) is the case.

With all the changes to Mastery and with CS becoming more powerful, will the 2p tank idea become an interesting choice again?

Also, what about the 5% extra damage on the PvP gloves? Surely, if two pieces with ratings that are off can be interesting for 10%, then one piece with less off rating and 5% could be so as well. If this has already been discussed, then I've missed it and apologize for bringing it up again.

@Ronark correct me if I'm wrong but wouldn't AW boost the damage of the CS which would result in higher HOL damage?