No, that's not really what I'm saying at all. Sorry for not being clearer about my assumptions, here.
I
am just suggesting that the Rogue should be able to swap his attributes around and buy up to a decent Wisdom so he's less great at Rogue-ing and much better at Cleric-ing, however.
If the player wants to do that. If it's somehow core to their concept that they be a crappy cleric, fine - go to town - but it shouldn't be necessary to make a mechanically poor character in order to "roleplay" it.
* I share reservations with @pemerton about buffet-style multiclassing, and don't like how it dilutes what should be archetypes down to a tepid and mushy point-buy system, but if the option is there, it'll work.