My opinion on CS arakune is that yes, he is a very, very, good character. Top 3? Debatable. The strange thing about Arakune, from myself playing him is that, against Bang, Ragna, Litchi, the matchups seem to be somewhat even. HOWEVER, Lambda, Hazama, and Hakumen, it is an entirely different story. Lambda-Arakune matchup is hardly any different then Nu-Arakune matchup. Hazama it is hard for me to comment on, because of the lack of good hazamas that are capable of playing on XBL. But with Hakumen, every fight seems like a chore, almost impossible to fight hakumen from an air-air standpoint as Arakune. So you become reliant on zoning with clouds(thank god they don't count as projectiles anymore). So then, you finally get hakumen cursed, but the fight is far from won. One well timing sword attack from Hakumen requires you to through yourself at the black hole where hakumen is free to keep you at a distance from it(and of course not throwing out any more bugs to refresh the time). Not only does he have the black hole, a well timed counter will lead to massive damage requiring a burst or simply Arakune is dead.
So TLDR; Arakune is an amazing character and should definitely be high tier, but I am not sure if he can be top 3 with some of the matchups put before him.