Will everyone lose their memory about turning to dust when the Avengers put things right?
I wonder if weird cults might spring up after "the rapture".
They could include The Controller (possible Ant-man 3 villain?), a Thanos was right cult, cults like the storyline in late 80's web of Spider-man and other weirdos (such as...?)

As for Avengers 4 I'd like to see (probably unlikely but...)

Shuri as Iron Panther (reverse engineered from Rhodey).

Pepper in rescue armour - activates after Tony goes missing for a certain period. Tony's final battle with Thanos using Sabbath's Iron Man song in it's entirety...

Adam Warlock vs Thanos, Ant-man gets up Thanos's nose, Nebulla transformed into a whole woman,

Possible death of Tony, Thor or Cap (Bucky replaces him as the new Captain America)
Ending similar to 2012 film, featuring Kamala Khan cosplaying as Captain Marvel...

and YOU?