Huh. You know I've read your FAQ's and still assumed Natural Spell was implicit to why the Druid was T1. Knowing it's not, personally makes me think it doesn't seem T1. I guess that'll always be a problem on rankings but I'm trying to input what I know, not impugn the tiers themself. And no, that opinion about Natural Spell opinion was my own, formed from gaming and these boards.
My point ko'ed, thanks for taking the time to address my post.
The reasons why druids are tier 1 are:
A.) Because with all of their buff spells AND wildshape, the druid itself tanks better than classes that specialize in tanking (heck, at early levels, a single class feature alone is better than fighters, and that's without the fighter's gear or the buffing animal companions get from their masters - and they get much better assuming the druid in question puts any effort into making them awesome).
B.) They're full casters that get 9th level spells. They get great de/buffs and good battlefield control spells, and they can also get access to spontaneously-casted minions (most of which they can buff to hell and back), and several of those minions get spells or spell-like abilities that, frequently enough, grant them access to the spell-lists of other classes (not even including the horrifically overpowered
shapechange).
C.) They can be a sneaky class, if they like. In the right surroundings, they can find traps, and they can certainly use their Tiny and Diminutive sized forms to scout. They're not
quite a rogue, but for a class that doesn't have 'scout' as part of their job description, they do a damned good job.
D.) And they can do all of the above simultaneously. They can't quite break reality into pieces, make the pieces sit and roll over, and automagically make it their bitch like a wizard can, but they come close. With a bit of op-fu, they can even play with the wizard's spell-list, if they want to.
Basically, any given druid (especially the ones that take Natural Spell - and really, what druid doesn't? - but even normal ones) can do so many different and varied and insanely powerful things at any given time that they're unholy terrors for DMs to try to reign in. Hence, tier 1.
And they get worse out of Core.