I think it's inevitable (no pun intended) even if it's just flashbacks or something. Thanos has entered the movie canon of iconic villains alongside Darth Vader and the Joker. You wouldn't even need Brolin if it came down to it.
Eventually, he'll show back up in one form or another. Sage advice for his son Thane maybe? Fodder for Doom to reflect on? He is inevitable.
I'd watch the hell out of a Thanos miniseries.Most definitely. They gonna start with Thanos D+ miniseries building up to something like Doom.
Yes when they do Secret Wars he'll be brought back to job to Doom.
Yes when they do Secret Wars he'll be brought back to job to Doom.