I think most Welsh people would say yes. Fixtures with Bristol, Bath and Gloucester are comparable to local derbies, and even the London sides are easy for fans to travel between. As a result there would be good away support at a lot of games.
A few years ago I would have said that the English clubs wouldn't want us, but with the financial issues engulfing some English clubs, if ever there was a time, now might be it.
I even think Wales would consider a 3+1 or 2+2 approach here, with the regions split between the Prem/Championship as that would solve some of the immediate financial issues facing the WRU/regions.
I don't have any issues with the quality of the URC, if anything the Welsh regions are the ones holding it back, but Welsh supporters obviously just don't have much appetite for it. Away travelling support is also non existant.