Really you had to go there. Just because 3E/Pathfinder are not as finely balanced as other editions does not mean that it it is a good idea to just say anything goes.
By RAW, the game is extremely unbalanced in favour of casters (particularly single-class or PrC-using wizards and clerics), certainly post-6 or 10, and indeed some would consider it "unplayable", RAW (I would disagree, but it's not exactly un-heard-of as an opinion - it's the main reason the E6 and E10 rules exist, which were once very popular).
Not mod-voice, 'cause I want to keep this more friendly, if that's okay.
RE, I think you missed the point - this thread isn't about the overall balance of games, or what is playable or unplayable. It is about the much more focused issue of whether a cleric/wizard can do this thing, in RAW, and maybe what would tend to happen if you allowed it.
"You went there" looka to be more about the broad critique of the 3e/PF rules branch, which was not really warranted by the topic, and could be considered edition warring if things in the discussion go sour.
So, really, let's not go there, hm?