This might just be a prejudice of mine, but it seems to me that the divine casters should, as a rule, be worse at casting than arcane casters. So, how about if we split their casting between Wis and Charisma? They need at least 10 + spell level Wis to cast those spells and get bonus spells based off their Wis, but Cha determines their save DC? This way, it's a lot harder to play a cleric who's good at everything, and he'll generally be worse off that the arcane guys. (We could also do something similar with the druid, though Charisma wouldn't work as well, nor Int, and the physicals are certainly out, so he might need a different fix).
I don't see a compelling reason for them to be a worse caster. I'd be more inclined to limit them toward more utility and indirect combat support except for offensive spells directed against outsiders and undead. Leave the blasting and enchantments to the arcanists. Leave the raw elements and nature to druids.
Personally, I believe there are far too many spells that are shared on too many lists. I believe this is particularly true after the publication of the splat books and Spell Compendium. The individual spell lists have a certain amount of distinct character, they should have more.
I don't see a compelling reason for them to be a worse caster.
Not to be contrary, but what about the heavy armor, d8 HD, and 3/4 BaB? Not to inflate their value, but they imply that the cleric splits his focus (and he does).
And that's why I'd push the cleric away from more direct combat with his spell list.
But direct combat spells are often inferior anyway. Evocations in particular fade into meaninglessness at higher levels. Removing them from the cleric's list makes him more powerful, since it doesn't tempt him with the flashy-but-ultimately-inferior. Hence why I think the cleric should have to work harder to be all-around good at casting.