If franchising does arrive I wouldn't rule out a new club starting in the superleague. Whether or not it would be based in London is a very different matter.
It's an interesting discussion though. Toulouse and Toronto had to start from the bottom, prove there worth and work up. I am not saying which way I think they should do it, but a lot depends on criteria applied. Should wasps get involved eg, good stadium, proven record as a yawnion set up, is that enough?