Maybe im missing something but as far as I can tell, this idea depends on the size of a community. Right now an international competition where clans from all over the world competete with each other does not work! We've seen that, as you pointed out in the cwb, the twpl and the ccs. While national tournaments such as the spanish or the polish leagues become more popular and are sometimes bigger than big international tournies such as the cwb at the zenith or the twpl and the css.

However, it did work in the past (twpl rome season) mainly because the community was more active back then. And I assume that it could work again if more players come back or start playing mp again. Another factor (obviously) is the mp support. Lags, leaks, NAT errors and the like can destroy all our best ideas. But if we have a stable, advanced and modern online plattform, nothing would stand in the way to stop us from organizing large and successfull international tournaments.