Priest does need a fix in the thought that Spirit is pretty much junk at the moment (Spirit is getting overhauled soon though, so I guess there it is), and it's their primary stat.
But outside of that, yes, Priests are babies in general. The only reason there isn't a flood of them would be due to their heritage in past games, all the work, none of the glory.
Undead Shadow Priest is about as close to god (no pun intended, I swear) as you can currently get in Warcraft.
Druid is a great healer and all, Restore is an amazing tree all around. But I think even spec'd as so, a Priest is better nine times out of ten, if simply due to Fade. Well, the actual GOOD AoE heal and a real ressurection spell are nice too.
Speaking of which, that was my biggest gripe when I sampled Shaman. I found it ridiculous that they get both a self-ressurection (which is now being buffed) AND a real, traditional one.
There are many times where you can take a Shaman or Paladin along safely as a main healer in lower instances, but you simply cannot with Druid.
Luckily this is rarely a problem due to the versitility of the three classes (along with the population of Shaman and Paladin), but it's a problem I have nonetheless.
Back to Priest though, it's funny that I pretty much loathed mine.
I think in retrospect, it was due to the fact that I wanted a heavier support class (Paladin is currently as close as WoW gets to that role on the whole, but sadly it's absolutely saturated with folks who have no idea what the class is for, and thus ruined it for the good folks) but was worried about efficeny between specing for Shadow and EXPing well but feeling guilty in instances, or specing for Holy and instancing well, but feel guilty while EXPing.
That and that I dislike the big church tie-in and the fact that wearing bathrobes into a War is lame!
Edit: Sorry if my posts are at all difficult to read, I'm trying to make them easier actually, heh.