It looks like walls have 2 primary combat benefits (ignoring the strategic level increased visibility effect):
1. Increased defense from ranged attacks, +3 for ground units, +1 for flying.
2. Regular ground attacks are funneled through a single choke point.

Questions about mechanics of walls:
1. Does #1 apply to all physical ranged attacks or both magical and physical ranged attacks?
1. Knocking down sections of the wall negates #2, but does it have any impact on #1 or does #1 remain in effect regardless?
2. Are there other benefits to walls and do they remain in effect after sections of the wall are knocked down?

I think it applies to all physical attacks,but not magic ranged attacks.

I, too, would like answers to this old post.

Taken from the MoM wikia site is the following info.

"When a section of wall is destroyed, it ceases to function as a physical barrier. Any unit can now freely move through the newly-formed hole. Destroyed towers are also passable to all units.

However, a destroyed wall section does not entirely lose its protective benefits. Any unit standing inside and adjacent to this wall section still receives +1 Defense (instead of +3).

Note that destroying wall sections - even all of them - does not damage nor destroy the City Walls building. In fact once the battle is over the wall is completely repaired, and will be as good as new at the start of the next battle - even if the next battle occurs during the same overland turn! "


http://masterofmagic.wikia.com/wiki/City_Walls#Destroyed_Wall_Sections

Hiding behind the rubble. Makes sense. And a good thing to know. This was news to me as well. Thanks.

All thanks belong to the people at the wikia site so be sure to visit it and register so you can ask future questions or look up answers on their very own page.

I wish city gates were impassable to attacking land units, excluding fliers, incorporeals, and other enemies naturally able to ignore walls. You should have to have some way of breaching the wall. Even a small defending force should be able to defend a walled city against an army if that army is composed of nothing but spearmen and cavalry.

Haha you must be a HUGE fan of AoW. (This was easily gotten around by your Hero unit having "Wall Climbing" which only cost 5 points).

In some ways I agree but in others I don't. It would give Draconians an even greater advantage than they already have and would require rebalancing them.

Allowing attacks through the gate at all times is reasonable given that the game doesn't allow the walls to be scaled by attacking forces. Making it totally dependent on 'wall crusher' units would also be problematic - it would be far too easy for the defender (especially with a wizard involved) to simply take out the wall crushing unit to block the rest of the army - engineers are pretty fragile and the other wall crushers aren't exactly easy to come by for most races.

That's the thing though: it's really easy to breach city walls. There are units that can smash walls, shoot over walls, climb over walls, float through walls, and fly over walls. It don't think it's too much to ask for an attacker to make some preparations to destroy walls. And I think the defender targeting the wall-breaching attackers is solid strategy.

It should be an option at least, IMO. I've played Shadow Magic a fair amount, and a little of the original (which I like better in many ways), but they aren't nearly as interesting as MoM.