I agree.
Saying that I think that the knife like weapons have a huge advantage against other melee weapons because of that. Lowering the gap imo could help to make other melee weapons more competetive. Instead more movement speed could be distributed in each character’s tree to compensate and archive higher mobility for an investment. This way the knife would still be the fastest weapon but to reach the current knife’s mobility, the players would have to invest into the movement speed. That would also allow them to boost mobility with other weapons if they desire so and are willing to pay the price.