From a movie stand point I don't see that being a very good movie. Hulk splits from Banner, Hulk Smash, army goes after Hulk, Hulk Smash, Banner gets Hulk back, end of movie. Its basically the same movie we've already seen before in the two previous Hulk solo films, its redundant. So unless its full blown Grey Hulk and we see him as some enforcer for the mob like in the animated series I just don't see a Green Hulk solo film being done again.
Really if any solo Hulk film has any chance of working at this point in the MCU, in my opinion, is to continue with Professor Hulk. Hulk has more humanity at this point in the MCU, its not just Hulk Smash anymore. They touched upon this in Infinity War when Hulk wouldn't come out, he doesn't want to just be used to fight. So any solo film would have to move forward with that humanity not back to Hulk Smash or it betrays the character they've setup and is cheap. And Feige is too smart for that.