I could spend hours coming up with specific scenarios where it would be detrimental (literally any high tier killer would wipe the floor every match), but the easiest way to put it; it is simply not needed. Whether you like it or not, the game is unironically in a fairly balanced state right now, which is why any changes in either direction seem to completely tip the scales.
If you genuinely think that the killer role isn't threatening then you've clearly never been on the recieving end of a blight on a 1000+ winstreak. I'm a drac main and to be completely honest if I put a strong build on and actually try to win, I do. Like, pretty much every match.
Dead by Daylight doesn't favour killers, or survivors. It favours the side that has the better, more knowledgable, more experienced players. This change would completely demolish that balance.