@400MillionBelis:
Now, people, let us not forget that the time-skip was for EVERYONE to grow more stronger in their own ways.
We can't say (read: can't) that Buggy still has his old chop-chop his body parts after two years as shichibukai. It would be real groaner to have Buggy be the same old weak Buggy without any new techniques and stuff.
You might ask, "Why would Oda have Buggy learn how to chop other people when Law already does that?"
Then, might I ask you, "Why would Law still have his same old, same old power after two years?"
I believe, and yes, believe that Buggy is behind that chopping of that samurai. But he has grown stronger after 2 years, but doesn't mean he'll surpass the likes of the Supernovae.
Maybe…
For you and all those guys that think this might be Buggy's doing…
STOP. WITH. THIS. BULLSHIT.
There's absolutely no evidence that Buggy is able to make other people split like himself. That would be beyond retarded because Buggy's signature weapons are daggers. The Bara Bara no Mi allows him to separate and control parts of his body. If he was able to do the same thing to his opponents, then his fruit would be awfully similar to Law and Oda is much more creative than that.
Also, how exactly would Buggy be able to separate and control other people's body parts? Is he just going to "wish" for his opponent to split their limbs? At least Law has the excuse to first make a "room" where only everything inside it is under his control. Buggy's ability is limited to his body only. The biggest improvement Buggy could make with his ability is being able to split himself in very thin parts to the point of being virtually intangible.
And for the love of God, stop mentioning Brook. His new powers make sense because the Yomi Yomi no Mi was relatively useless when compared to other Devil Fruits, so Oda decided to fix that. Buggy's DF is decent on his own right.