I also dislike going through steam, specially after i got game maker studio. So i didn't get it and am waiting for a sale here, directly from scirra instead.
I got mine via steam, and to be honest, I should have just brought it here. Steam is not geared towards applications.
I knew about steam not being able to open multiple instances of c2.
I knew about the file association glitch.
I figured for the discount price I could semi tolerate it until it was fixed.
BUT, it just isn't worth it - period. Gonna, try to make $5000 from this steam version so that I can buy the business version here.