I've also been having some thoughts on this recently.

Mainly, that it might always be +ev to call with draws on the flop, as long as the bet size is relatively small in comparison to stack sizes. This is just because if we hit that gutshot on the turn we'll definitely get our money back, and if we miss we can just fold the turn.
It also gives us a chance to take the pot away if villain was just c-betting and checks the turn, we can fire out and sometimes take down the pot.

So OESD and FDs i definitely call on the flop, and sometimes i'll float with a gutshot. If you hit it, you'll be paid if villain has a made hand and if you miss you can sometimes take it away on the turn.

Sounds ok?

Clar