EWR is a Unique Airport.
Terminal A, located in Elizabeth, NJ (thats why you see white taxis there, and not at Terminal B and C), the Airport Property is owned by the City of Newark, with a long-term lease to the Port Authority of New York and New Jersey. (the last lease was paid up front, and is how Newark financed the Prudential Center)
Terminal A is owned by the PANYNJ, but managed by United (and was before the merger), while Terminal C is managed by United (Continental Previoualy), and Terminal B is managed in-house by the Port Authority.
Anyway, I could see United upping its investment in EWR through a public-private agreement to overhaul the Terminal, which compared to Terminal C, is severely lacking in any amenities. Any additional spaces added would allow for retail spaces which in turn spell revenue. I could see at a minimum, connectors between the A1, A2, and A3 concourses. Unfortunately, I do not see an easy solution for connecting Terminals A and C, with Terminal B in the way.
On another note the PANYNJ has plans in place to totally rebuild Terminal B, which is interesting, as Terminal B is in the midst of a multi-stage rebuilding project, which included domestic arrivals being moved downstairs a few years back, into the reclaimed parking area. The plan is eventually to dump International arrivals downstairs (via escalator/elevators in the area of the current International Arrivals waiting area)