Paladins basically can't run out of mana if they play correctly, and they can accomplish this with blues/Kara/t4 gear. All t5 and t6 can offer them right now is lots of +heal for bigger heals, since they don't really need longevity. That's a problem.
That Illumination change...hurts, if true.
Most healers that I raid with will jokingly say "nerf paladins", but they generally agree that something needs to be done to improve the healing trees of other classes. This Illumination change totally came out of left field...perhaps from the same designers that are brewing up the latest set of alchemy 'fixes'?
Now what we would end up with is the healer population in raids going up to meet new demands in healing endurance, which lowers overall raid dps, which makes the dps races that seem to be a hallmark of TBC raiding that much harder to win. I suppose the Paladins that gear up in the direction of +healing/mp5 rather than +scrit/+healing won't feel it as much, but for those that have invested countless hours gathering spell crit gear, this is devastating.
Hopefully this change doesn't make it past the conceptual stages, and instead meaningful improvements to other healing classes in terms of raid utility/endurance are applied.
Looking at a WWS parse from Morogrim last night...
I was #2 on Effective Healing, with low overhealing. I regained 10.6k mana from 4 Super Mana pots, 5.8k mana from Mana Tide, 5.3k mana from BoW, 1.5k from Mana Spring, and 1.5k from my Warmth of Forgiveness. I had mana oil, mageblood, mp5 food, etc., on me. I was completely OOM and running on fumes for the last 5%.
A paladin with objectively worse gear than me was just behind me at #3 on Healing. He got back 20.3k mana from Illumination alone, not to mention another 4.6k from Spiritual Attunement being healed after Earthquakes/Graves.
I consider that excessive. Even paladins in my guild agree it's not unreasonable. A paladin in a shadow priest group (due to the Attunement synergy) will still have infinite mana anyway. With the proposed Inspiration change, this paladin still would've regained over 10k mana from Illumination, and had to use fewer pots/consumables to equal my mana pool.