It sounds as though you are in the same situation that I was. I had a Prior 4WD that I used with hard boots but lacked the time and skills to get the set up to work anywhere other than on the groomed stuff. I want to be able to ride anywhere on the mountain without bein unduly limited by my gear. I ended up trying soft boots on the 4WD but it was too narrow and the binding heel would lift the edge out of the snow on agressive heel-edge turns. I have size 9 feet, but it was the binding, rather than the boot that was causing problems.
I got a Volkl Cross with Catek freerides on it and was much happier on that set up. It does not carve as well as the 4WD with plates (at least not with me driving) but it is a far more forgiving setup in the rougher, steeper and narrower sections of the mountain. The Volkl Cross is getting a bit tired now and I have sold the 4WD and acquired a Tanker 172 with Nidecker bindings. I really like this combination, and have not been out on the Cross since I got it. It floats much better in deeper snow (The Cross tends to dive) but is still quite quick edge to edge and in the bumps. I'd like to try a Tanker 200 sometime, but it is obviously not going to be very good in the bumps.
I have not tried either of these boards with the hardboot set up although they are both supposedly very good. I have the original TD1s with Raichle boots and I think this rather unforgiving interface may have been part of my problem on the 4WD. I should really get rid of the TD1s and pick up something a little more forgiving.
I'm not sure if any of this is helpful, but there are plenty of softboot set ups that carve pretty well and can be used with either soft or hard boots.