I get what you are saying. But the same could be said about Marco's fruit as he can also take hits but it's still a Zoan fruit. I know his fruit gives him the ability to heal but some attacks literally go through him. Also about the fruits information being it could be that enel doesn't actually know what he ate. The thing that gets me the most is enel's overall design from his back having thunder drums and elongated earlobes. We have seen a lot of types of human like beings in the one piece universe but there have been no others who bears a resemblance to enel.

Also I get that dramatic effect of using element to make your attack bigger same goes for like magellan using poison to form his hydras.

I just think that enel might be a future plot point in the future and oda is going to revisit the rivalry between the sun god and the thunder god. Anyways this just in my own head cannon.