Depends how much importance the evil side of the D. clan will get (previously Xebec, now Teach)
For now Imu is more important to the lore, especially since laughtale -> Mariejois is the obvious sequence of events.
However I'm still not convinced Teach is a simple fight for the pirate throne, there has to be something bigger than this.
1. Introduced since chapter ~220
2. Very similar to Luffy in character, both are dreamy & goofy
3. He's an evil D. opposed to Luffy
4. First recorded man to eat 2 devil fruits
5. Never slept in his life
6. "weird body" "they"
7. Heir to Xebec, Roger's strongest rival and the most heinous existance known to man.
8. Like Luffy he's constantly shunned by Oda, like getting low diffed by Magellan, running away from Akainu, kinda scared of Rayleigh, when eventually we all know he's going to surpass all legends. Basically the only villain to receive the usual Shonen mc treatment.
9. Wields the strongest (2nd?) devil fruit in the verse, one as special as the Nika fruit.
10. Scarred Luffy's role model and inspired his jolly roger
11. Captured Ace, already had beef with Luffy
12. Already anounced ambitions bigger than the pirate throne
Currently, imagining Teach as the final villain is as hard as thinking a random Imu can replace Teach, favoring
@Blackbeard for now.