Related Midwest signed a letter of intent in March 2015, but only now concluded the deal with GMH.
Transit access to that area is certainly a concern, but I don't think it will prove a huge problem. The first step is to either extend the 36 Broadway bus down Wells-Wentworth, or add service to the 24 Wentworth and route it that way—or both. That immediately gives the area better service than West River North has. A new bus line via Kingsbury-Wacker-Wells-Wentworth would give all the newly developing areas pretty good service.
Over the long term (30-50 years), we should route the Larrabee-Clinton subway through there:
A station on the Rock Island is pointless unless you need to go to Tinley Park or Joliet; one on the Red Line at Clark is problematic for operational reasons (curve and slope).
The bigger transportation problem for this site will be giving it adequate east-west access.
Sixteenth Fifteenth should be continuous from State and go into it, but some guy who lives in a townhouse there had the ear of Mayor Daley and demanded it be broken up with two cul-de-sacs. CDOT will make the perfect the enemy of the good when it looks at the clearance underneath the Metra tracks, where you can only get about 13 feet, and will refuse to construct a substandard underpass.
This is the fight worth fighting for the future of the city. Otherwise you end up with a fourth closed-off compound in the South Loop.