Well, holy &%$@!
I mean, sure, I'm up for it. Let them fight.
... but at the same time I doubt the Kong that Godzilla will fight will be of the same continuity of the Kong in Skull Island, 'cause a Godzilla-sized Kong limits the typically Kong-esque things you want Kong to be able to do in a Kong movie.
More importantly, this suggests a healthy working relationship between Legendary and WB, which I was worried about in the back of my mind.