if some way posible the doors should have their hp shaved down litle since it took quite some time to knoc them down and if team has no volunteers with 2h axe's it takes, imo, too long.
another idea for that to counter the task of hitting those doors would be battering ram, simply put just a big log or stmh like that and say 6 to 8 ppl divided on each side could use that to break down the doors, this however can be hard/impossible to make work, but i feel it could give some more colour to the game and would require team effort to use
id olso would like to see ladders to scale that 1st wall, either make them as item wich you can buy/make in game at the cheast much like in raid gamemod, you can get torch from that spawn chest if you forgot to buy it when selecting equipment, or just same way as in native, eitherway i olso think if they are made buyable/buildable thay should olso be destructible objects
thease are my suggestions since the defender and attacker spawns are all rdy pointed out here
i have only played 1 or 2 games of siege but its seems to work quite nicely and is a lot more fun that native siege