Obviously starting hand strength has some importance in O8, but there are really three types of hands from a pre flop perspective.
1. Hands you shouldn't play.
2. Hands you need to raise with.
3. Hands you REALLY shouldn't play.
Your point about the low limits being different than the big games is obviously a good one. And actually could lead into a favorite argument of mine dealing with whether it's better to lean to beat the game in general, or the stakes, or the table. But another day for that one.
For me figuring out what to play is far easier done by just understanding the dynamics of the game than by using a chart or point system. Now, before you get mad at me for bashing point systems... I get it. They help you know what hands are valuable pre flop.
But if you were to graph pre flop hand strength in Texas Hold'em I think you would see sort of a logarithmic line. Most hands are trash. A few hands are playable. Very few hands are really great pre flop.
O8 is a very different beast. Almost ANY hand has a fairly large potential to have a chance at winning at least half the pot. As you obviously know the question is more about what hands are likely to get you in trouble and which are likely to create edges.
If I am playing primarily from something like a point system, I am making myself a sitting duck. Even at the lowest limits on stars I know all the PLO8 regs who are basically using points. And I can avoid them quite easily. Beyond this, I can exploit them by doing thing as simple as betting the pot when a card comes that changes the top hand or takes away the low, JUST because I know what their formula will tell them to do when I bet that way.
But IMHO the biggest caveat to using a point system (see i said 'caveat'. Not problem, or even weakness) is the fact that it might draw your mind away from the WONDERFUL fact that O8 is a POSTFLOP game. The game is fought most effectively after some cards hit the felt. In fact there are two things that make me salivate wetly... when i see people overvaluing big pairs preflop, and when a fish sits down intent on playing a hyper aggressive NLHE style preflop game. I LOVE picking my spots to take their money when they will see me as a fish "sucking out" on them.
Which brings me to my last little bit...
Poker in general, and especially o8 is a game of finding, or creating edges. Position, and table dynamics is more important, IMHO to the cards you start with. You can isolate the guy who just 3bet his AA97r or you can hammer the nits blinds, or you can freeroll youself into someones entire stack by drawing when you have the odds
to do so. All three of these are ways to outplay the guy using a 'system'.