The wall sections could be like the LOTR Uruk-Hai Army "battlepacks". A small section of the wall and a few soldiers of both factions.
It would be a good way to create bigger walls for the castle (or get some usefull parts fo moc'ing) and a great way for army building.
In my 9474 and 9471 all Uruk-hai have 3 bars design, except the berserker, while all the fleshies have filled pegs.
I checked another set i have here (4204 - The Mine) and 2 of the 4 minifigs have the 3 bars design while the others have filled pegs.
Haven't checked other sets yet.