I think both Mach and Bullet Punch should get a range buff.
Why?
Seeing how all other punches got increased to a 2-tile LoS, the current range of Mach and Bullet Punch, it wouldn’t make much sense for people to get those moves because the other moves are much more useful. However, if those moves got a range buff too, it would be balanced somewhat more.
Into what?
I think a 3- or 4-tile LoS would do, because that wouldn’t give it too much range for a punch, but still be balanced against the elemental punches and Drain Punch. Maybe the accuracy could be reduced a bit, as is normal for 3-tile or more ranged moves.