IDK, I'm not level 70 yet on my PLD yet but I'm going to go out on a limb and say that even if we used Holy Spirit and Clemency as freely as you advised, you still wouldn't notice out MP pools going down all that much. I just ran the 63 dungeon, trying to get PLD up to the next tier dungeons and even when effectively spamming Holy Spirit and Clemency after my Aggro was established, my MP would not go down past 60%, if even that. Enemies were just dying way too quickly that it felt largely unnecessary to spam them to a point that I was going MP starved before the next mob pull and even on bosses, I still have to maintain aggro as my 1st priority and against good DPS, it's not like I could spam either move without risk of losing aggro.

Then, there are external thing you need to be aware as well.
Is someone giving out MP via a role skill?
Did the PLD pop a potion? (Weird but it's possible)
Are you just looking at the wrong times?

Regardless, I do like the changes made and while I am still leveling my PLD, I don't really expect anything to change upon hitting 70 about these skills that would make the situation any different than what I'm currently experiencing.