You have a valid point, that the magnitude of the impact from this change is difficult to estimate at the moment. But even when this change ends up in only a 5 or 10 percent reduction of our mana regeneration advantage, why should we accept it without disagreement? Frankly after we already got an indirect nerf with slow mitigation and are constantly challenged with faster paced content, while still having a class model designed around long duration fights, we shouldn't accept
any further arbitrary disadvantages or reducing of class-specific advantages.
I have no problem debating the size of needed tweaks, maybe we really get lucky and only minimal adjustments are needed. But nobody could seriously claim, that this change will have no impacts on group and raid dynamics altogether. For the record: i have no problems at all with this change helping some soloers. I always found it pretty lame, that current EQ blatantly puts some classes on such a big soloing disadvantage. All classes should have a reasonable shot on soloing for worthwhile XP, when they feel like it - or no class.
It's great SOE tries to come up with new ideas to make the game enjoyable even if some old-timers may disagree, most people do not want to wait 15 minutes for clerics to get going again. But atleast they should take the time and investigate, how
all classes are effected by such changes.
To the discussion on the EQ-live forums, a lot of those posters (not all mind you) simply don't care as they aren't affected by this change. Would be intereresting to see their reactions, if some game functions related to their own class abilities would change

.