Nope. Imu isn't even favored by the Gods.
Imu will be scared of Luffy and Blackbeard because their ambitions far exceed his own.
Luffy and Blackbeard's Haki will make Imu's look like a little puppy's later.
Think about it! Imu got scared of that Haki Knot made my Joyboy. If Luffy's Haki gets anywhere near that, then Imu is going to end up screaming around again
He seems cool and composed, right now, but he freaks out at the mere thought of Joyboy. That speaks volumes.
You're thinking the end war is just going to be everyone using ancient weapons for a final fight against the world government. This leaves problems with a very important thing - The Will of D.
The Will of D isn't just to break free of Imu's control, it's actually to fulfill some Ancient Belief and Values System related to the Ancient Kingdom. However, I don't think it's just Joyboy's belief, because it's the entire Ancient Kingdom's beliefs and they might not all be the same, and if they're not then that means there is a potential for the Ancient Kingdom's technology leading to both good and evil things. That's the true disaster.
Imu has been largely outside of this element of the story. He doesn't seem to know the Ancient Kingdom's beliefs at all, and he couldn't make their technology work either (he needed Vegapunk to do that and Vegapunk was hundreds of years ahead of humankind in his understanding of technology).
Yes, Imu has been a driving force for the current events in the story, but none of the current events surround the Ancient Kingdom yet.