Warp fruit being regarded as the strongest in a df hunting crew makes you realize how broken the ope fruit is.
The difference is (as far as we know) Van Augur doesn't actually have to swap that person with anything
Law's fruit is only actual teleportation when it's raining
That's why when he fought Hawkins we saw him throw a rock in his direction before he shambled over
If Van Augur can teleport anything including himself and objects you could argue that he has a top 5-10 fruit in the series
It would make observation almost useless
Even with future sight you can't see the future unless you're looking at your opponent
If a fast top tier teleported behind you you're not reacting to that