There's a big difference in totally suppressing a person's powers and just being able to override them and make contact. Only Blackbeard and ocean/sea-stone have shown an ability to actually suppress powers. If you completely take away a fruit users abilties most of them are going to be completely worthless. They rely on the fruit and have almost no real combat ability of their own. Think of Crocodile and Moria, they wouldn't have been a challenge for Usopp if they didn't have their fruit abilities much less anyone else in the crew. Even Kizaru and Aokiji seem like they would be insanely weak without their abilities.