I think the haircut is less systemically broken then the print limit. The haircut shifts existing price risk from STEEM onto SBD holders. If they don't like having more risk, they can sell, at which point the SBD price will drop, SBD will start getting converted and its total supply will drop. It at least tends to push SBD in the right direction. The print limit is the opposite: If SBD is overvalued, then it doesn't get converted, the supply steadily increases and then printing stops, which makes SBD more scarce and potentially drives the price even higher (WTF?!).
I understand you have expressed concerns about the haircut but personally I don't see it as a problem (other than potentially impairing the utility of stable SBD at some point, but we are so far from that now, not something to worry about at this point).