I posted links to designers of the game discussing how the cleric could be more effective at melee than melee characters, while also being an effective caster, as well as one of many discussions comparing power levels of most classes.
Though, yes, there is a poll on one of the links that roughly mirrors the poll in this one I suppose.
I was only googling for a few seconds, though. There's plenty more exhaustive evidence, deconstruction, and math behind it, and the problems have informed numerous game products since, including 3.5's many nerfs to spellcasting, tome of battle and 4e's improvement of non-spellcasters, etc.
In general, 3e stripped away many of the limitations on casters by vastly increasing their access to spells, scaling saving throw DCs, easier casting in combat, loss of casting time, removal of most spell penalties (aging, system shock, etc). Even in simple areas like hit points, a caster used to get less benefit from constitution than a fighter, but now gets as much... and got better ability to improve their constitution, with powers like polymorph and bear's endurance.
There's a reason a ton of that stuff got nerfed in 3.5. It was a bit wild.