Avengers 4: 11 Things It Must Avoid

4. Relying On Nostalgia Bait

If the rumours are to be believed, Avengers 4's plot will revolve heavily around time travel, and possibly see the surviving Avengers travelling back to classic MCU set-pieces - such as the Battle of New York - in the hope of gaining the upper hand over Thanos.

Though this could bring a nifty novelty value to the movie, the Russos will need to tread carefully to ensure it doesn't just feel like a navel-gazing, self-satisfied victory lap that coasts on audience nostalgia for the previous movies.

As helpless as most audiences are against nostalgia - just look at the continued success of the Jurassic Park franchise despite its general awfulness - it'd be a shame if Avengers 4 got a little too cynical with the wink-wink references to prior films.

Will It Happen?: Doubtful, thankfully. Though time travel is a tricky beast to figure out, it's easy to have faith in the Russos and co. given their track record for tackling difficult-to-adapt characters and moments.

If the plot really does involve revisiting classic MCU battles, it's a safe bet it'll be done creatively and with plenty of good humour.