Before you laugh and say, "DeNiro is a serious actor, he's not an action icon," let me just just give you 3 words: Rocky and Bullwinkle. Look, there was a time when Robert DeNiro was above films like The Expendables. That was what? 30 years ago? As Grudge Match showed everyone, DeNiro and Sylvester Stallone have real chemistry together. These two graduates of Roger Corman's Film School are BOTH master thespians. You can laugh at that idea all you want but Stallone wouldn't be the icon he is, he wouldn't have attended the American College of Switzerland and the University of Miami (obtaining a BA degree) if he wasn't. DeNiro could play a great villain in these films. Or, perhaps he could play Stallone's long lost brother whose gone afoul of the law? The final Expendables needs this, Bob. And for those who think he isn't one of the world's foremost action stars? Have you seen Righteous Kill? Taxi Driver? Or, a little movie called The Godfather 2?
With a career that has had its share of ups and downs, Vin Diesel has carved out his own career path as possibly the coolest of the action legends. As a result, this thinking man with muscles owes Sylvester Stallone a debt of gratitude. Stallone broke down doors for buff actors before there were even doors to smash. Vin Diesel could very easily slip into a bad guy role in The Expendables 4. Maybe he and Stallone are related in some way? Perhaps, Stallone's Barney Ross shows the younger Diesel the error of his ways? Or, maybe Diesel is just icy bad and he gets blown up or something?
Wouldn't it be great to see Keanu Reeves take some of that Speed and John Wick action sensibility, and put it to extreme use in The Expendables 4? This could really elevate the final Expendables. There are a bevy of action roles that he could play that would further bolster him among the action legends. Perhaps this action star starts off as somebody on the side of Sylvester Stallone and Co. and then he murders one of the Expendables? Maybe the fourth film in this franchise takes on the idea of mystery dinner theater? Members of The Expendables are being offed. It's up to Stallone's character to figure out who the killer is. Reeves could play a character helping him find the killer. Imagine the standoff when Barney Ross finds out that the person helping him is really working against him? This idea practically writes itself.
Look, young people loved this action icon in Guardians of the Galaxy. He's also going to be in the upcoming Avengers film, the Blade Runner sequel, and he's a beloved character from the WWE. Does one of the biggest action stars need any more of a reason to be in the final Expendables movie?