Is calling a flop with 23 a good or bad idea
What is the percentage of 3 low (8 and under) cards hitting the board
What is the percentage of an Ace hitting the board in omaha on the flop and by the river
I know that the deck has 60% low cards in it
I assume that the percentage of an ace hitting the board would be lower because the players are taking 40 not 20 cards like in nlh
Odds of a low being available are approximately 60% (I wrote a piece with one approach to the math, and Brian Alspach's web site has a couple of articles on it). Of course, the three cards making up that low might be A23, and nobody's hand can compose one, but that's not the question.
The probability of an A hitting the board in Omaha is the same as in Hold'em (about 22% on the flop, 35% for the whole board). The way you consider the unknown cards is the same regardless of 40 cards being dealt in a 10-player Omaha game rather than 20 in a Hold'em game...with one primary difference. It's not a huge difference, but definitely something to consider.
In Omaha 8/b, the A is a VERY valuable card. If you're on the button in Omaha 8/b and there are four people already in the pot, it's safe to assume that there's probably at least two aces out there. That assumption, IMO, is one that you can't make in Hold'em with nearly the same degree of certainty. If you take two of the aces out of the deck because players have them, the probability of an A hitting the board are cut in half, down to about 11% on the flop, 17% for the board). And you could very easily find yourself drawing to one A for the nut low, or drawing dead entirely.
So, what does this mean to your question about playing a hand with 23? Well, IMO, you should NEVER play a hand where 23 are your only connecting low cards. Something like 2369 just gets mucked. If there's a bunch of people in the pot already, and I'm holding something with more straight possibilities, like 2345, 2346, 2356, etc....I might want to see a flop with it in a limit game (never in PL 8/b unless I'm limping in from the button or SB).
That's just me, though, and I'm talking as a guy who plays low-limit. In a higher-limit game with better players, I'm far more hesitant to play even the hands I just mentioned.