One thing. Galactus was first portrayed as a rabid hunger-monster, who couldn’t control himself, so I’m okay with Dan Slott’s portrayal here, being duped by Reed forging an Ultimate Nullifier convincing Galactus.
We have to remember that Galactus continues to show-up on Earth, like there is a fatal attraction here. Why doesn’t he eat the Kree home planet or Sakaar? No, Galactus has a preponderance to visit Earth over and over again, so we have to conclude as he can’t have Earth, it tastes better than other planets. (The same goes for Dormammu).
Locking Galactus away like this in Latveria seems like a ticking time bomb. It’s never going to bite Victor in the bum? The whole idea seems crazy. Would you lock the Phoenix on Earth? Galactus is a cancer; the Phoenix is an out of control, planet-wide bushfire. Why bring them here?