Yes there is such a thing as too much spirit.
You don't want to bottleneck.
You want a perfect balance, no one can tell you what that balance is, you have to heal, and find out for yourself. Too much spirit might cause you to go oom just as quick as too little spirit, because you might need to use larger heals to bring people back up after a burst.
I have around 2700 spirit before all my trinkets and set bonuses are ramped up -- once they are, I've got about 3248 spirit, 104k mana pool, and 12.8% haste. I'm now able to actually cast a flash heal and greater heal without burning all my mana (not the case when I had crappy gear in the basic heroics). But these boss fights in the Firelands, they have been a real healing test for our raid. All the big damage/burn phases are at the end (unlike tier 11 with the exception of Al'kir) and not only are you expected to follow all the mechanics of the fights perfectly (i.e. tornado dodging), you're expected to heal up mass amounts of raid-wide damage at the same time. We haven't fought Majordomo yet -- we plan on facing him this weekend. I am not looking forward to all the damage he dishes out. I'm going to need all the spirit I can get.
So in my honest opinion, there is no such thing as too much spirit.
I also think theres no such thing as to much spirit.
because mana ca directly be transfered to HPS by using more expensiv heals. (instead of reforging the spirit into a HPS stat)
for example by using more FH,FH,GH combos, which is very nice HPS.
On the AoE sector, you cant really do more HPS when you have more mana, but you can just ceep on hitting that PoH butten even more, and even longer :-)
<= spirit fan. I love it as holy!
I dropped some spirit gear before T12 but now I'm switching back to spirtit gear. If you are progressing in FL chances are there is going to be a lot of screw ups and with a lot of bosses having burn phases you are going to need as much spirit as you can get your hands on.
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