I couldn't work out if D had simply forgotten the at the end of his post, but it appears to be serious!
The main flaw IMO is that the whole idea is based around solving a problem that, to most people, simply isn't a problem! Dunfermline got 70 points this season, do people think it is wrong or unfair that they didn't get the chance to battle for the SPL title or at least a place in Europe? Nope. Likewise, next season, should Hamilton be allowed the chance to show how high up up the SPL they could get? No because at the point at which a "split" was taken they hadn't done well enough and were on the wrong side of it, so the best they can hope for is to finish above the teams they are thrown in with.
It's like in golf, you miss the cut, you're out, even though you might possibly have gone on to win the tournament if you'd been given the chance to continue. Well you had your chance in the first 2 rounds and you blew it.
The odd/even thing then removes the best thing about having the split in the first place, the chance to maximise the number of "6 pointers" and meaningful fixtures at the end of the season. 5th v 9th in May? Yawn.
As a minor point, you've then got the difficulty of balancing the number of times teams face each other home & away. At present, equilibrium relies on the teams at the split being in the half of the league the SPL expected them to be in - which is difficult, and contentious. With D's idea, it relies on predicting whether a team will be in an odd or even position at that time!