Yeah, the SHs are real strong. But they are still far away from emperors, that is why Law is teaming up with Luffy (Kid is likely to join in as well as he has beef with Big Mom). And mind you, Big Mom seems to be far from the strongest emperor, and I don't think that Luffy+Law will be enough. But time will tell.
Oda stated that Enel is still alive and kicking. And I think he said he will introduce him again at some point!
Not sure about that last bit. However, if Enel was down on the Grand Line, he would roflstomp everybody and have a bounty of 600 Million Belis
That's real good for the Grand Line, and that's what Oda said in a interview.
Yeah, well Law has been with us since Sabondy and seems that he is and will become the friendly rival of the Pirate King, that doesn't want that title. Something like Whitebeard was to Roger. Luffy and Law can have small skirmishes but in the end they are "friends" and can do alliances. However, Law has his own agenda and he will be in the manga until the end. People still think that he might have Luffys heart in his possession after he fixed him up. What need that would fulfill, I don't know. But it could be a twist later in the story.
But with Law, comes another unfolding of a story that has several connections. Law-> CC -> Don, and Don is portrayed as the puppet master that pulls all the strings for everything in the shadows, so all brokers, ties to Yonkou & Elders, his view on the world. Welgo and the G5... even the swamp guy, Caribou from the fishman arc is probably connected to him!