What's the point of a 5D

I shoot weddings with a 30D. I've hired guys who shoot with a 5D and I've seen their files.

The big issue, for me, is the egregious concave distortion on the wide end, especially the 16-35. It's so bad I thought the guys where in a funhouse mirror show at a carnival, or something.

I thought the whole point of full frame was to take advantage of wide angle lenses, right?

How are the 1D cameras with wide angles?

Patrick