There is a word you need to use more often on your players. It will solve many of these problems immediately.
That word is: NO.
If a player comes up to you 5 minutes before the game, hands you a stack of printouts and expects you to approve them for his character immediately, that is a perfect time to use the word.
I'm sorry if this comes across as snarky. It's just that I have seen too many posts where DMs feel victimized because they have been hit over the head by their players with some new rule/feat/spell/PrC/whatever from the latest sourcebook. This is a button with me.
Regardless of who published the book, YOU have final say on what goes in, and what doesn't. Period.
It's your game. Always remember that.
To answer your original question, although clerics mostly do healing, protection and buffs, they have always had some offense ability as well, especially at higher level.
In my game, if a player wanted to use cleric spells from a new sourcebook, I would first carefully review the spells. Those spells I did allow, I would introduce to that character slowly. Remember, clerics only request spells to prepare from their god. The god (you) can deny these requests.
I like the idea of going on a quest for lost clerical knowledge, and may have to use it someday.