Paladin Cecil could've been way more better and Dark Knight had flaws too. Paladin Cecil does not know hardly any white magic spells All I've had throughout the entire game are Cure1,Cure2,Exit,Sight and Esuna. There might've been maybe two others one, but he misses the ones he really needs like Life1, Life2, Cure3. It really sucks that he doesn't have them. He doesn't have Holy either and he calls himself a holy knight.

Dark Cecil was useless against undead and his dark attack cost him some of his HP which was also a flaw.
But overall I still prefer Paladin over Dark Knight.