Is it just me or are people being deliberately obtuse?
The crit to mp5 model proposed was a simple one. But it was a post model not a projection model.

The premise stated was that you could with the tool work out how much crit had counted as MP5 in a fight that you had already done.

So you take a parse of a fight you have already DONE. Take the number of heals and divided by fight length. This gives the number of heals per second that you cast.
So note the fight has already finished. You have decided already how many heals where enough to win that fight. You cannot change what you did in that fight.

So now you want to know for THAT fight how much MP5 was my Crit worth.

Then look up the MP5 value for that cast speed (note that it will overestimate the MP5 value unless all your heals where Holy Lights)

It is a simple modeling tool. It is not nearly as useful as RAWR but I doubt that it was ever meant to replace RAWR.

This tool will NOT tell how much MP5 your Crit is worth in the next fight even of the same boss. But then no tool will ever do that.

But the principle is correct that a certain amount of crit will save you a certain amount of mana per cast independent of starting mana.

Yes, this is evident. It is also irrelevant. If all the model does is force you to do a bunch of unecessary maths in order to reach a conclusion you could have come to in about 30 seconds of looking at WoL / WWS / WMO reports, then it's utterly useless.

Either way you look at it, it's bad. Either it's a tool that gives you an uninteresting, irrelevant piece of data after the fact, or it's a flawed model which misrepresents the worth of MP5 and crit.

And yes, X crit will save you Y mana per cast independant of starting mana, that's why people are so adamant that crit is modelled as saving mana, and not giving or restoring mana, which is how Abe is trying to model it. I'm not sure if you were agreeing or disagreeing with this from the context of your statement, so forgive me if I'm being redundant here.

Contrary to popular belief, my original post was not to give a guide on how to gear. The numbers were not to tell the player how much Mp5 their crit is worth at all times. It was to show that Mp5 has been seen as a crap stat, and unrightfully so. To give a better idea, I did some napkin math on what total casts Mp5 and crit gear give. I compared a paladin with 35000 mana, 40% base crit (talents, buffs, etc.), and 275 Mp5 to a paladin with the same mana, 55% crit, and 0 Mp5 (both using Libram of Renewal and Glyph of Seal of Wisdom). The difference between them was to trade 15% crit from gear into the Mp5 equivalent. I included mana gained from replenishment (90% uptime) and Divine Plea (used 4 times every 6 minutes). At the 4 minute mark, the Mp5 gear gave 113.474 total casts, and the crit gear gave 113.212 casts. The longer the battle goes on, the bigger the gap between the two increase. At 7 minutes, crit gear gave 159.643 casts and the Mp5 gear gave 165.642. With this stat comparison, Mp5 would give more casts per battle. Note: I used a combination of my earlier equations and a program I developed to give me these numbers, point out if they are wrong. Edited out: (Also, because the Mp5 gear would have Holy Lights that have a higher average cost, the Mp5 gear gives significantly more mana).

I do not intend for this example to account for everything, go find a spreadsheet for that. The point I'd like to make so far is that Mp5 gear has a bad reputation, and the numbers don't justify it. Even in the original post of this thread, it is said that Mp5 is a "pretty crappy stat," and says Mp5 gear may be better, but only because of better itemization. Someone recently said that we should understand the stats we use and not rely entirely on programs to make gear decisions for us. Having Rawr pick your every decision, I believe, goes against the basis of this discussion setting. No hand-holding. We should have a better understanding of the stats we use, but I certainly don't think it is a bad idea to use spreadsheets if you are trying to optimize your stats.

Although 3.2 is here and this doesn't matter anymore, I still wish to get the word out that Mp5 gear was generally at least on par with crit gear, and potentially better.

Now I might be missing something here but that statement seems nonsensical.

I presume he's referring to the breaking of 4pc T7 for MP5 gear.

Edit: Good catch. I skipped a step in my head. The extra mana gained from the Mp5 gear goes towards those extra ~6 casts.