you are over-estimating Enel...
his lightning\matra aside, Enel was a horrible warrior, had low fighting stamina and was quite 'slow' in his movements.
the only thing that he had was the lightning based invurnability, which still has some weaknesses.
other than rubber, probably every non-conductor matrial could harm him, and there are quite a few of those, not to mention he probably couldn't avoid other logia based attacks.

his mantra is good, and all, but it depends on his movement speed, which isn't very high (imagine him trying to predict rob lucci's speed, impossible).

leavinng us with his electricity attacks. and for heavens sake, Nami could (theortically) divert those, so anyone with similar abilities could do that. and there's still the option of using a metal rod to 'aborb' the hit, and simply 'fastmoving' the attack.