Maxperson
Morkus from Orkus
Yeah. That's why for most skill checks in my game need you to be proficient to even get a roll(or auto know) the answer. Anyone can auto fail.I'd specifically try to do the opposite: make one useful in one way and the other useful in another. Between them they still wouldn't cover all the bases, and nor should they; ideally you'd need at least three more characters to even try to cover them all and even then there'd be holes.
Trying to make everyone useful in all ways was - kind of - 4e's mantra; and history shows how well that went in the long run.

I don't believe that everyone should be able to roll for everything.