I don’t think he has the BEST of everything, persay, he has worse guard damage than Mi-Na, Sieg, and Groh, his pressure is worse than Raph’s or Maxi’s, his damage output relies pretty heavily on pokes outside of SC, his aGIs are in the top 3 best in the game though for sure, he also has either the best or second best SC behind Mi-Na’s. Kilik is a pretty godlike jack of all trades, but he’s not really the absolute best at anything besides probably safety and pokes
I was using an hyperbole, but besides those that literally live and die by a tool, I really think he's the best in everything.
Damage wise he's only second to the big hitters: Nightmare, Siegfried, Astaroth and ivy, and even then his SC damage is so insane it's second to none I belive. His guard damage is just the same.
His range is insane, only second to Astaroth and Ivy and on par with Mina. All characters that aren't even half as good up close.
His pressure isn't as oppressive as Maxi's or Raphael's, but it's definately safer, and honestly better too. Raphael preparation basically puts the opponent in a favorable 3 way mix up, while Maxi's has a lot of holes once you know the MU and where to look.
What else? His lows are only second to Amy's, his WR buttons are second to none and his Soul Charge is the best in the game absolutely free, not even arguable after this last patch.
Also his evasion is amazing: every single one of his buttons either a tech crouch, a tech jump that jumps mids for some reasons, a tech step or multiple of those combined, and that's on top of being extremely safe on everything, since he's the safest character in the game (and I'd say there's no argument to be made here). Plus his step is great too.
His safeness also gives him great turn stealing possibilities with GIs, and he's got the best post-GI game in the roster. Thank God GIs were nerfed by the way.
Finally you've already talked about his aGIs, which are top 2 in my opinion, and don't get me started on his Ring Outs.
Dude he isn't weak or even average in anything, and yet he still has top tier tools all around. That's the Kabal formula.