I'm still trying to think of some of my favorites, but one thing I want to make perfectly clear is that it took a whole lot of effort for anyone to fuck up Aparo's pencils. So, I guess my question would be who was the worst person to be teamed with Aparo.
Obviously, no one inked Aparo as well as Aparo.
Here's some original art for sale from later in his career, some of it with different inkers.
I never cared for DeCarlo's inks on anybody's work, including Aparo's. I'm almost inclined to vote for him simply because he did so much of it. However, it wasn't incompetent and Aparo's pencils still had some of their trademark quality.
Kelly Jones and Bill Sinkiewicz are both interesting but they more or less overpowered Aparo's pencils. Still, the artwork is good, if not distinctly Aparo, so I can't call it a complete failure.
Dick Giordano's stuff is surprisingly weak, given how well he worked with Adams and others at DC.
Of all time, however, I think I'd say
Sal Buscema.