To me, acceptable but not ideal is anywhere in the city and within 10 minutes of a subway. Admittedly some such locations will be far from ideal.
Given the real estate market in NYC, the chances of finding a prime location with excellent transportation and a vivid nightlife infrastructure with a lot big enough for a stadium, and where you won't get outbid by someone who will use that lot 365/year instead of 30-40, approaches zero.
I think NYCFC's biggest problem with Yankee Stadium is not the turf or the scheduling issues, but the unrealistic expectations it has created in its fans.