Now I don't see how this helps two 6,000 seat stadiums, but I'm just bringing up that if there is a market in CT that's strong, this is it. Honestly, WAKA would probably kill it with some kind of complex like the one that used to be in Vernon (only for baseball/softball) because they could use fields for all of their different sports.
My guess: looking to host regional events and tournaments on the relatively cheap; attractions like pro lacrosse, or CrossFit events, that I imagine pay up for venues way larger than what they need. High school-level, D3-level, less popular or lower level D1 college-level sports events. Music festivals too. All the accommodations essentially on-site. Drive to Albany, Providence, Boston, or Keene in under 2 hours. Stowe VT, Portland, NY all just over 3 hours away. Next to an international airport servicing the Eastern seaboard, Eastern Canada, and as far West as Minneapolis.
And adult club leagues, as you said. I'm 27 and I'm totally with your whole point on that. They'll be looking to cash in on camps too but that's beside the point for the justification for 6000-seat stadiums.
I'm not sure it'll work