Or keep it like in Ins2. By having increasing difficulty throughout the game, you will either need the bots to start very easy, or increase difficulty until it gets borderline impossible - Borderline imposssible is nice by all means - But keep it like that from the start of round one so everyone who likes and voted for highest difficulty can play on hardest difficulty all along. Same case with those who prefer lower difficulty.
Increased difficulty throughout the round will also have the drawback that the game may consist of both skilled players who would have voted for hardest difficulty if given a choice, and new players that would have voted for lower difficulty if given a choice. When you have a vote early round, you can leave server if not satisfied with the choice majority of players wanted to play on - This is also possible with scaling difficulties, but even with different scaling difficulties options, most of the round will be played below the players skill level, which is bad imo.
BTW: We need survival mode, this NWI announcements about not keeping players spread thin with too many gamemodes is not working as intended - Have many gamemodes like last game, people will group up anyway because multiplayer with many ppl is more fun - Still being able to play your favourite mode/modes from time to time would be great.