I dont think hub-centre steering has been used for those reasons, we've seen it sparingly, most famously in the bimota tesi, beautiful bike:
old:
new:
The problem is conventional upside-down ohlins forks mount at the headstock, and allow the frame to be designed and shaped to give the best flex possible when a bike is on lean angles greater than 30degrees. If you add hub centre steering, you lose a lot of area to work with.
When the bike is on full tilt the frame and swingarm bend and twist, if these were 100% rigid, a bump would overload the tyre and put you on your arse.
This exact reason is why we find ducatis with beautiful frames, they are steel trellis frames, they dont need to be big as the steel is more rigid than aluminium (like the twin-spar japanese sports bikes) but the challenge is to design a steel trellis frame with the right flex in the right place, they aren't just randomly made.
Suzuki actually made a trellis like frame out of aluminium whilst incorporating the twin spars:
The swingarm is equally important in this respect, unless braced they will twist under load and cause accelerated wear.
So when looking at the entire handling package of a motorcycle, hub centre steering is a massive step backwards in todays motorcycles... they just wont handle as good at 45 degree lean angles as their standard counterparts.
just to beat this point death... the Bimota (the same guys who built the hub-centre tesi) made the SB8R... they wanted to use a full carbon fibre frame, but found it would be way too 'stiff' causing problems when racing... so they adopted this as a compromise: