Technically, I'm just passing through
I don't think that common adherence to bad idea makes said idea good tbh. Also I'm big not-fan of "balancing" through screwing interface up.
Up input is actually more problematic when you need to do it from neutral since you can jump if you hit it too early, while with other direction you can afford hitting the key early.
Point being though, characters have a lot of options in neutral, so key combinations are necessary. Plus like it or not, side reversion of inputs is a thing and have strong practical impact, some setups are based on that. In the middle of target combo though, that is not true and those inputs become redundant.