In the second draft, they actually encountered Annihilus and he was 20-feet tall and cybernetic…I pitched him as the T-Rex from Jurassic Park and the way he would be sort of hunting and attacking them, and it seemed like he was the one who killed Victor and they barely got back through the portal in time, but it felt like a really fun twist or fun way to use Annihilus that we hadn’t seen.
However, given the movie’s troubled production, it was one of the many ideas that got scrapped in the process, and the plans for a potential sequel were shortly dropped after it bombed among fans and critics.

As for Miles Teller, despite the disastrous reception to his Marvel debut, the actor was open to the prospect of returning to Marvel. But considering it was the script that held Fantastic Four back in 2015, for any potential return, Teller’s priority remains the script and the crew (via The Digital Fix).
The thing that I look at for pretty much every project is scripts. That’s first and foremost. The character, the director, the cast, the cinematographer: all of those things, I think, go into making a decision. So, if I thought all those things were in place, and we had a really good chance to succeed, then yeah, I wouldn’t have a problem with it.
With multiverse being a major factor in the MCU, the chance of Miles Teller’s return as Richards in the upcoming Avengers flicks isn’t completely off the cards.