I'd be shocked if Funimation didn't get Dragon Ball Super, so that's more of a when than an if. If Funimation gets the license soon & the dub ready by the time Kai wraps up, Super should likely be DBZ Kai's replacement.
Funimation was founded on the idea of getting DBZ over in the US. They have an in with TOEI, which while it hasn't guaranteed every single one of their shows has lead them to a long and fruitful relationship. Also everyone else who has tried DBZ met with mixed results. TOONAMI is the place besides some sort of crazy Netflix/Amazon/Hulu money deal. It's definitely the home for it on cable.