The siege mechanic in this game is honestly the most dull of any total war game i have ever played, here is why:
Ladders is not something everyone should be walking around with. i think making it so that ladders always takes at least a turn to assemble would be awesome.
Building on top of the ladder issue Siege towers could be made a much bigger part of some sieges, by making tier V cities have "tall walls". making it impossible for ladders to be used. Sound familiar? Total war Medival 2, this was done.
Artillery in siege is weird: honestly there are so many things i don't understand about artillery in siege battles. Artillery pieces cannot be placed so that they can't be bombarded by towers, i have never tried that a tower was destroyed by artillery, once have i seen a wall break (because a had 5 units great cannons hammering it).
Artillery were historically made for sieges, but in this game the only useful pieces of artillery are the ones that can shoot over the wall...
Grids on walls, i don't understand why i can't place units on the walls as i please, they snap into some stupid grid which in honestly don't understand the purpose of.
Wall stairs (defenders side), thy aren't the stairs of the walls more prominent as they where in Rome 2, this made it possible to make sure that armies couldn't just run into the city, i.e. a small fix to units routing into the city and regaining control.
Now there are several more problems with sieges of total war, in my opinion. but these are some of the things i cannot fathom haven't already been addressed
I'm sorry i wen't on a bit of a rant, but these problems have annoyed me for some time now, and since most of the problems i have was better made i earlier TW games, i had to let it out somewhere.