I'm Exdeath, and I can block any attack from any angle, then counter you instantly with Delta Attack for close, or Almagest from far away.
and we have infinites.
Exdeath: Slowest character in the game and takes a lot of practice to get the timing down from what I've heard.
Cloud: Considered too slow and predictable. Constantly viewed as one of the worst characters.
Sephiroth: With the exception of his buffed Hell's Gate, his HP attacks are considered to have the most predictable and avoidable HP attacks.