My Great Big Suggestion Post

[Farore]

1a for your global cooldown complaint, NO NO NO, NEVER EVER. i enjoy ff 14 combat BECAUSE i dont have to spam 80 button presses a bloody minute, if you want this so badly, go back to wow/ rift, shoo, off with you.piety adding mana regen... it does in a sense, as mana regen is based on max mana, though piety doesnt affect it much (6.5 mp per point iirc)

also changing the gcd would require the game to rebalance EVERYTHING.. also you can lower the gcd by stacking spell / skill speed

1b theres plenty of variation between classes, the "homogenisation" you claim with tp and mp and changing that directly contradicts your request for more cross class things. as you wouldnt be able to use any skills from other classes because you dont have the rescource.
also most classes play vastly different...

Is it fun, pressing one button every 3 seconds? I really don't think it's fun to wait around for a much longer time than I'm actually fighting. If you want to wait around, go back to the console Final Fantasies. This is an MMORPG, not an online console game. :P

Even stacking as much Skill Speed as you can possibly find, you might get to 2 seconds, at most. More likely you get to 2.2-2.3.

I know it would need to be rebalanced. I expect it would take a while to get it all ready, but it's worth it, if you ask me.

I don't think you read all that well. I didn't say anything about cross-class, or any of that. :3 The classes don't really play very differently at all, if you take the time to take off the goggles and look at it.