An example of why you can't expect developers to do your parks planning for you...
From "Public hearing focuses spotlight on Takoma/Langley Crossroads" in the Gazette:
Bob Wulff, senior vice president at B.F. Saul, which owns the Hampshire-Langley Shopping Center, said the developer was largely in favor of the plan but took issue with a proposal for a 1-acre green space in the plaza. Wulff said a grassy space would simply turn into a "mudhole," and the 1-acre allotment was too large and would be better used for more commercial space.
Wulff said the developer would prefer a smaller urban plaza with more hardscape?and less grass.
"We would argue that is not the right use," Wulff said. "Form follows function. This is an urban plaza next to a transit station. It's not where you play Frisbee. It's not where you sit on the lawn and have a picnic."
I can't say whether or not 1 acre is too much. It is the size of a 2/3 of a typical block in the L'Enfant City in DC. That can be big. OTOH, this is a big area and will have a transit system and a fair number of taller buildings and needs some open space.
But this illustrates my general point that the profit imperative is what drives developer agendas for the most part, and only to the point where marginal contribution to revenue is positive do developers "contribute" to community objectives.