I've never had a good offensive backhand - the two-hander was always awkward and ineffective, so I mastered a slice. This is useful for rallies, but worthless as any offensive tactic.
I've finally started to develop a topspin one-hander, but I need to work on consistency. I'll hit a few shots with good pace and spin and I'll feel like Federer, then I'll clunk one into the bottom of the net or into the fence.
Thing is -- I think I'm doing the same thing! I'm very conscious of my footwork and swing from low to high with topspin.
Wonder why that happens from time to time...I don't think it's game-ready.