What do you mean by bullshit gimmicks? As I see it the series managed to keep its core gameplay. Sure, 2070 and 1404 had different factions to use, but it was more than a gimmick.
hey we need to do something for next game. I KNOW LET'S ADD HOME CITY !!!
hey we need to do something for next game. I KNOW LETS ADD GREEN VS DIRTY !!
hey we need to do something for next game. I KNOW LETS ADD MOON CITY !!
Problem is that they don't want to improve core of game they instead focus on bullshit because that bullshit will look better on boxart.
On other hand:
- diplomacy ? What diplomacy ?
- proper military ala 1602 ? what military ?
- maps are still size of 1602 ? What we should work on maps ? Why ?
- natives ? you mean those cultures that are threated as bonus ?
- trade network ? What trade network ?
- more random events ? what events ?
- aliances with various non player factions ? Pirates ? Mercenaries ?
- spy network ? what spy network ?
This series after 3rf part started to look like Stronghold sequels past 2nd game where developers instead of polishing core of game they are focusing on bullshit and do needless stuff.
Also games got progressively easier. 1602 economy wasn't superhard but it was easy to run out of materials.