ive had an indea for a proper PVE gamemode-Last stand. Mechanically it would be similar to MvM from Team fortress 2->a group of players would have to defend some area from waves of attackng bots that get progressively harder. They would try to capture some point you would have to defend. During their attack they would have varous support.
tanks- pretty obvious- slow easy to kill with proper AT gear, but dangerous if left unckecked
snipers- would spawn far ways from the objective in an area with good cover, staying back and picking defenders off
smoke artillery- they would always hit the same poition, either obscuring you vision as the defender or providing smoke cover for the attackers
flankers/paratroopers- spawn behind your lines, (maybe) dont attack objective, but instead cause havoc among the defenders(killing players, destroying engi structures)
image as an example of how it could be(plese ignore regular game spawn/capture markers):
