Lynette being a Burgmeister is probably the most popular theory, certainly has more behind it than being a family we just barely heard of. But I'm sure DPC knows that and is probably planning to subvert our expectations. That being said, the fans would care much more if MC was a secret Burgmeister: it'd strengthen the bond with Rusty, make MC campus royalty, put him on a higher level than Tyballs as far as social standing (Tyballs would probably be the only guy who even cares about that, but it'll piss him off so that's a plus), play into Jill's belief in destiny, even more girls would want to bang MC, maybe give MC some soft power to help Maya as well as take some heat off him and Bella (bit of a stretch), and it might be able to help Neil somehow so he doesn't have to bust his ass every day.
MC being a Wallace doesn't have the same impact, and would also count for less since this isn't W&W.