I think the problem will fix itself really soon. The people exploiting it and treating it like "demo time" or "hey I can play this short game for free" will very quickly get locked out of refunds.
I don't like the idea of a price floor. I just got a refund for a very cheap game that was unplayable for me. I happen to like my couple of , thanks

I also wouldn't like devs "getting away" with bad games just because they don't cost enough.
I've seen indie devs (the one linked above for example) saying 10/15 mins should be enough for all games. They are being very, very silly. I've not gone through the settings menu and seen the intro in a bigger game in 15 mins after starting (and that would also include the time for the first time setups and such, which can take some time). 2 hours make it possible to tinker with the game to maybe make it work before giving up on it.
Mike Bithell (an indie dev I admire oh so much) tweeted about this too...
(among many other tweets about it, seeing it from the consumer perspective)
A "solution" I can see would require more work from the devs and a remade achievement system. I noticed that it told me how many achievements I had gotten in the two games I sent a refund request for (got them accepted today too, it went fast and smooth!). I had gotten zero cheevos in the game I couldn't play and one cheevo in the other game. If the cheevo system could have special achievements that put "marks" on the account this would be a simple way of seeing if someone played through the game.
A cheevo put somewhere half-way through the game could get you a silver star (or whatever) and make it very hard for you to get a refund without a very good explanation. A cheevo from the end of the game could give you a gold star and make refunds impossible. But meh, it would never happen.