I totally disagree, get basic stuff done by the designer, but I find it completely changes as programming happens. You figure out things won't work the way you

I totally disagree, get basic stuff done by the designer, but I find it completely changes as programming happens. You figure out things won't work the way you thought they should, you figure out better ways, etc. Get wireframes down, so you don't spend thousands on designers, and then realise you have to spend thousands more.