Okay living about 10-15 minutes from this property let me see if I can get my pluses and minuses out.
Minus - Leaving the city of Chicago, I believe Chicago is the only city with all four major sports within the city limits.
You lose history, although one can argue the mistake by the lake took care of that.
I am sure they will lose some city fans that come to games/events, but the Bears really don't care about Soldier Field.
Positives - You go from a 7 acre site to one with over 300 acres
The stadium will be easier to get to, the Metra already has a stop at the location and I am sure an expansion of transit will happen.
Stadium will be 5 minutes from a major highway, and have plenty of parking.
The ability to approach the stadium from 360 degrees will be helpful. Getting in an out of Soldier Field is a nightmare it literally takes longer than the game, and with the limited parking, impacts the ability to tailgate.
There has been some rumbling that this is a step to making the team attractive to a buyer. Virginia is old, and if rumors are true the family won't be able to pay the estate tax when she passes, so they will be forced to sell at that point, no clue if that is just rumor or if there is truth in it. This just gives them a really attractive option to build a state of the art stadium and entertainment complex. This is the way forward for NFL franchises, hell Balmer is doing it with the Clippers.
I think it makes a ton of sense, and frankly look forward to going to a game there if this ultimately happens. I haven't been to Soldier field since 2013 and I don't have any plans to ever go back. Just way to difficult to get to. Honestly the only reason I would go to Soldier Field now is if ISU played there, which is very unlikely.