In pro roller hockey, 3 on 3 is the standard procedure for OT (it is naturally a 4 on 4 game anyhow)...I've seen it go to 2 on 2 and 1 on 1 before. Both would not be considered hockey where I come from. Once lost a game in OT 2 on 2 before and absolutely blew my top...
Next time my team is subjected to 2 on 2, off of the faceoff win at center to start the period, I'm pulling the goalie for the extra skater. Go in 3 on 2, if you can't score, you lose. I'll take my chances, rather than watching 2 on 2 take place for more than 30 consecutive seconds.
3 on 3 in the NHL would be interesting...unless teams play it not to lose or scared to make a mistake, then it sucks, because you only get one support triangle out of it defensively and it's difficult to get sustained pressure. I'd rather see 10 minutes of 4 on 4, then a tie. But since the tie thing seems to be gone, I guess a shootout. The NHL has a thing about killing novelties, I think we've seen too many shootouts, they've lost whatever pizzazz they've had...same with the outdoor games. "They love one, huh? Well, then I'll bet they'll go ape **** for 25 of them!"
3 regulation win
2 OT win
1 OT loss
I'm almost tempted to say 1 point each for getting to a shootout and not awarding any points for winning just to discourage teams from getting there, but I know that's not exactly fair or practical. It's a tie...with a happy ending, I guess...