There are
39 Pokemon with a base speed of 60 and precisely two of them are actually viably capable of beating Starmie - Magnezone and Abomasnow. These Pokemon do not commonly use a choice scarf because they already have OU viable sets that are generally better and allowing them to outrun Starmie is unlikely to change that much. Magnezone is already plenty good enough without a buff and Abomasnow's hail is just annoying now that it doesn't last long enough to properly abuse. On top of that, it's not like Abomasnow is unusuable - you're not increasing diversity by any great degree by allowing it to revenge kill Starmie - hell, i'm pretty sure SDef Aboma could already pretty much beat Starmie, so it's not even gaining anything in that respect.
It feels like (and don't take this the wrong way) you're really desperate to latch on to any reason you can to support lvl 50 and thus you're trying to throw any fact you possibly can onto the pile with out actually considering the factual implications of the change. Hell, you spent half the thread moaning that OU is overcentralized and then said you thought a change that would undoubtedly increase centralization might be a good thing. That's wildl inconsistent.