I don't agree. There are many Mons against which you have no counterplay if you are unlucky (just right now I got swept by Returntomonkey because I had no psychic resistance), but the entire roster won't be nerfed just for that. If you fear this frustration feeling, just don't play randbats formats.
This gimmick is very original and shows the metagame self-refering by punishing too long moves, it would be a shame to lose that that can only be seen in such an SSB metagame.
It's not just self-referring, this gimmick also nails a large amount of vanilla moves as well. 12 characters is not very long, especially when you consider thay many moves consist of two or more words, and spaces are also counted for this gimmick. And I've been playing Staff Bros formats for years, ever since the original iteration, and this gimmick is imo easily in the top 5 most broken sets that've ever appeared. Although the recently buffed snake is also up there...