On another front, I'm wondering what you guys think about vertical movement in a skirmish game. I suppose Mordheim and Necromunda both serve as classic examples of what I am talking about.
Strictly from a players perspective, does the idea add interest to the gaming experience? Perhaps it is more effective to use in specific scenarios? What do you think?
Verticality adds interest, no doubt. The amount of verticality that works depends on the setting.
For most settings, I'd say no more than two floors above ground, and only in certain circumstances (maybe a watchtower or church tower), otherwise keep it to one floor above ground (most buildings that would stay standing wouldn't necessarily be very tall).
You could have taller buildings, but not have those floors necessarily accessible; you could have special rules/equipment for climbing up buildings to inaccessible areas.
Variation in levels allows for overcoming line of sight obstacles and allowing for alternative means of traversing the table, while also potentially exposing you to ranged fire as there is potentially less cover.
I never like high-up terrain in setup zones, nor do I like people being able to set up on a level above ground from the get-go - too many snipers and heavy weapons automatically just placed for covering the entire board before even starting. I used to think that in Necromunda only vents allowed for deployment above ground level anywhere, until I started playing and found everyone placing all their high terrain within their deployment zones.
You could have a terrain system that set out a number of terrain pieces for a given board size and game type, and assign each terrain piece a value based on height and size; then, players could have a point-based buy system (as they do with gangs in any other system) to be able to place terrain pieces, with a cost modifier if that piece is placed in their deployment zone or in their opponent's deployment zone (scatter= 0.5x cost, then #x cost where cost is the number of storeys, or some derivative thereof); you could also make it cheaper to place in the centre of the board in a similar manner.