I really don't see how a tennis player getting an MBE "throws the whole system into disrepute, as opposed to, say, resignation honours giving awards to a PM's cronies, or the cash for honours scandal, etc etc.
MBE is only entry-level honours anyway, and it is worth point out that Emma Raducanu didn't "win one grand Slam tournament", so much as "become the first player in the Open era to win a Grand Slam as a qualifier", and incidentally she's also the fastest Slam winner in terms of main draw appearances, winning on only her second attempt -- the previous record was four.