I think it depends on the criteria one sets for success. If the criterion for success is simply designing a functional champion, then Aatrox's rework is, overall, a success. If, however, one chooses to add additional factors, such as originality, authenticity to the champion's base identity, or the complete elimination of their gameplay issues, I'd say Aatrox's rework is a failure in all of these respects. The kit is not original, with a Rioter publicly admitting that Aatrox was designed to be Riven as a Juggernaut, the champion is certainly not authentic to his old self, as his playstyle, personality and overall identity are entirely different (and, again, deliberately so), and new Aatrox has already begun showing some problems, including several that he previously had (e.g. binariness, especially relative to his sustain, and dodgy counterplay in lane), plus some new ones (his Q feels super awkward to use, his E is largely considered unsatisfying, he tends to punish immobile enemies too hard, etc.). I don't get the feeling he's going to do particularly well, particularly since Galio, a champion whose VGU had very much the same problems, has ended up in a terrible state a year after the update that was meant to guarantee his long-term success.