Lag, MP shortages and other annoyances.

[Estellios]

If you are using Shroud of Saints correctly then honestly the only thing that will be killing your MP is Raising people. I always try to keep up DPS even in the story mode fights and never have any issues as long as Raise isn't needed. If you have to throw out more than 1 anyway, typically your party isn't doing so hot in the first place and needs to do their part to not get hit by AOEs.

In 8-man stuff you will usually have a BRD which alleviates the problem a ton.

[Zetor]

If you are using Shroud of Saints correctly then honestly the only thing that will be killing your MP is Raising people. I always try to keep up DPS even in the story mode fights and never have any issues as long as Raise isn't needed. If you have to throw out more than 1 anyway, typically your party isn't doing so hot in the first place and needs to do their part to not get hit by AOEs.

In 8-man stuff you will usually have a BRD which alleviates the problem a ton.

Oh, I can keep aero + aero2 + thunder on the boss without really running out of mana (and those abilities don't really do that much damage overall)... what really hurts the mana bar is when I need to assist in burn situations, which means Stone II and Holy.

My experience with Holy in particular was that I could cast it MAYBE once on a boss fight - more than that, and my mana bar would disappear if the tank wasn't overgeared (and thus needed more than just divine seal + cure / regen and the occasional freecure to keep up). There were fights like Aurum Vale's last boss (or Garuda storymode) where adds need to die ASAP, and if the DPS can't take care of them, the group is hosed. It's annoying to have this powerful AOE spell at my disposal, and yet know that if I use it, I won't have enough mana left to keep the tank up.

Bards never seem to use the mana song in DF pugs, even when asked... could just be my luck though.