Also, I think it's possible that legally, the clubs can't be stopped from entering a new competition, as long as they respect all the rules imposed by the FIFA/UEFA competitions that they take part in. I don't think it's written anywhere in the rules and regulations that you can't participate in a non-FIFA or non-UEFA competition. And don't think it's legal to impose something like that, because FIFA/UEFA don't own football alltogether.
So, I think theoretically, we could have CL and Superleague coexisting, with Superleague being done around the CL dates, so that the participants in Superleague would not breach the CL rules and draw hefty penalties in all competitions under FIFA ruling (including World Cup and such). But it would be a matter of time before the competitions will get into a conflict, and the penalties for breaching CL rules will be very drastic with zero tolerance.
Would be funny if the teams will play in both competitions and use subs in CL, and the real players in the Superleague to further undermine FIFA and UEFA. But it's all theoretical anyway.