Among the things being talked about is making sure the boulevard can handle the MAPS 3 modern streetcar, and that the bridge for the railroad tracks between downtown and Bricktown be able to handle future rail expansion.
Underpass walkways could happen if there's something worth walking to in the middle. That's how it works in Paris at the Arc de Triomphe for example.
On whether ODOT or the city has final say:
The city says ODOT has the final decision but has been amenable to everything the city has asked for so far. But ODOT has still said that the city has final word. They have not yet given a united and clear answer. I suspect ODOT truly does have the final say, but they wouldn't do anything the city doesn't approve of unless there was a really compelling reason.