Space for Expansion in EWR

One of United base is in Newark. With only three runways and all space for gates used up- is there any more room for international/domestic expansions?

Alternatively, do you think UA use JFK as an international hub and EWR as a domestic hub? Workable?

KJFK is maxed as it is with AA, DL and JB. There’s plenty of international flights in and out of KEWR already.