What feats? He has no Observation Haki feats, no Armament feats, and one page of using Conqueror's unconsciously. Ace has nothing that suggests he's good enough in Haki to defeat Enel. Giving someone with zero Buso feats strong enough Buso to defeat a Logia is also blowing things out of proportion, as you are giving value to a category that the manga has currently given zero.
Anyone with any Busoshoku Haki of any level can, technically defeat a Logia. You're hyping Enel up too much. His Devil Fruit is superior to Aces in terms of destructive capability, but lightning doesn't effect fire (other than making Flames stronger and hotter). So, Enel would only complement Ace in combat anyways.
Besides that, you really don't get a scope of how essential Haki is to the New World, and for someone like Ace (of that Caliber) not to have it is simply ludicrous.
I am giving value to something most likely, which doesn't add anything to a characters strength as we already know where Ace stands. You're giving value to EoS Nami that hasn't happened yet.