If you're playing a Ret paladin and are running out of mana, you're doing it wrong. Even with this change the only remotely threatening thing to a Ret's mana pool is that there was no mention of a reduction in mana cost for Crusader Strike to match its CD reduction.

I'm not running out of mana except in long boss fights or chain pulls, and a potion usually gets me through those. But in addition to the extra crusader strike costs, this change means that instead of 0.25% of your mana ticking back per second with a 100% uptime, you'll get 0.20% of your mana back per second with a 62.5% or 71.4% uptime (with set bonus).

So let's say that you have 5000 mana (for ease of math) and the fight lasts one minute.

Current: Uptime of 60 seconds, for 750 mana returned over the fight; 15% of your mana pool.

3.2 Talented only: Uptime of 37.5 seconds, for 375 mana returned over the fight; 7.5% of your mana pool.

3.2 Talented and set bonus: Uptime of 42.85 seconds fpr 428.5 mana returned over the fight; 8.57% of your mana pool.

Now, these numbers may adjust up if there are other replenishment-providing characters in your raid, but even if you're lucky enough to always get the buff (not certain in 25 man content) you'll get 600 mana back per minute, or 12% of your mana pool.

This doesn't sound like much over a single minute. But after 5 minutes of fighting, your best case scenario is that your mana bar is 15% less full then it is now; worst case is almost 40% less mana at that stage of the fight.

Maybe it will be off set by not spending money on FoL or Exorcism.