Well your advantages over others in the same boat are fairly obvious:
1.) You have access to a quarter of a million unique visitors every month (for a limited period)
2.) You have proven that you can create compelling gameplay with relatively simple tools (flash) and can get a team together and actually finish a project.
So the key now is how to turn that opportunity into your next online game and make some money from it. If you go with your own IP this time around, you will at least maintain the option of making money from it, if not now maybe later.
You have one leg up on anyone else making an indie web-based game, which is access to a relatively large audience. Try promoting your new game there and you’ll learn very quickly if there’s any chance of making some money from it! Like others have said, another demo with some pay for play levels, people like the content then it might just work! I think you should have a go! ;) But I would say that eh!
And there’s also http://www.shockwave.com/ as an additional route to promote your game!