>>48897976He would have his fishmen strength and all that, except he couldn't swim, defeating his natural territory. So unless the DF gave him some awesome ability i.e. being a Logia or Logi fruit (elemental fruit) I reckon it wouldn't be worth it.
From the people with DF's you've seen alot of them are shit, like the chick who's power was soap or some bullshit.
I mean she had the 6 skills (speed, air jumping,etc) that all those dudes had and then gets a DF and forgets all about them, fail on her part.