I think some spells should grant siege attacker and be able to target and damage walls.
Comet of casandora should be able to smash a hole, piercing bolts of burning and assault of stone should be able to damage them as well. I'm sure there are some spells I'm missing or are yet to come.
In a similar way to vauls anvil.
Walls could have health based on rank and race.
I suppose Ikits nukes should be able to as well
I like all the races. Equally. Wood elves are just the first among equals.