I love it, but I do think it is too required... I guess some things never change. It really pains me to see that the raid can't function to its full potential when I'm absent, but I usually attend our progress nights so it hasn't proved to be much of a problem yet.(Currently I am the only SPriest in the guild and we have no Retadins/Survi Hunters)
I personally have never had any problems with mana, but that might be because I am a huge fan of crit and I prefer it over haste(I don't avoid haste, I just don't like it as much). I also have quite a large chunk of spirit on my gear, which I haven't stacked at all and I still somehow find myself at 643 unbuffed.
I'm finding that my Shadow Fiend is usually used for the damage it brings, rather than the mana :P