Your math is correct, which is why I felt in a previous post that this would be a slight increase to ret dps, along with the mastery changes.

The problems I see is that you are wholly dependent on luck for those procs - you can easily go 30 seconds or more without a divine purpose proc, then have like 3 in a row. In a long fight on one boss, the RNG should even out. This leads to 2 issues:

1. If you don't get lucky, you're single target dps on adds can really take a nosedive - and there is not a darned thing you can do about it.

2. PvP - Ret pvp is really bad as it is, and assuming Crusader Strike is the only thing that can proc Divine Purpose, this basically completely eliminates ret as useful for damage dealing, except for those 20 seconds every 2 minutes you get to use avenging wrath.

Btw, with ret pvp, I don't want to make it out to be like it's completely worthless as it stands right now. A great ret paladin can maximize himself to do some decent damage, use his stuns and CC, toss out some heals. Problem is that equally skilled and geared warriors and death knights will completely own face on a ret paladin, and their rotations have very little RNG, as well as more consistent gap closers and snares. In other words, a good ret pally can hold his own right now, but is at a decided disadvantage when trying to deal damage. The changes as listed are going to put them at an even worse disadvantage.

Really seems like this is some kind of payback for those 3 minutes ret pallies were OP way back in 3.03 or whenever that was.