battles could have different maps depending on fort size, i mean literally more stages; 1 stage for small, 2 stage for medium and 3 stage for larges,
the small one is just the regular inside of large fort map;
medium has two stages, the first one starts with grass and walls and second stage is inside the fort;
large start on meadow with trenches and terrain, proceeds to walls and last stage is on the inside.
there is a limit for people in each stage, how many are joining next is shown; offline people are auto enlisted unless removed by general, while online you can choose to join on the next stage or not, this way the off folks go first or are kept for later. to move to the next stage would require control over territory in the form of occupying slots over an extent of the areas in that stage, chosing either to clash and hold position or give room to the enemy troops. the first stage is always advantageous for attackers, the second stage is balanced and the last stage is the last stand for defence but with enough covering for attacking troops to find a breach.
before battle, fort owning town can rearrange features on their side of the map and so can the attacking town on theirs, so the map choice is not always fixated thus allowing different approachs with tactics for both leaders to develop and counter. offline troops can be rearranged by generals and troop control can be regained once online.
additionally owning a fort provides the limited number of participating towns world buffs like xp, $, luck, drop.
i am to believe no other game has a war game mode to the likes of a Thr West Fort Fight but structure and targeting mechanics were never changed. you should be able to aim manually and tank bullets for others, and nowadays owning a fort changes no much to gameplay despite all the effort into xp maxxing and upgrading gears.