The same way the Leviathan was effective: heavy armor, heavy weaponry, little to no maneuverability. It adds a great game element IMO much like the "Galactica" with swarms of vipers.
Looking REAL nice...decent looking meshes also, I dig the realistic element to the characters especially the faces...good stuff...when is the game out btw?...
ooooooh! now i get it!!! people will think you're aiming above them while you're actually shooting them in the face! element of surprise and all that! <3
i gave it a shot. it was pretty fun. then again creating a massive rolling ball of destruction that is made up of all the elements it comes in contact with is just fun anyways.
Ammo is the same across the board for gun types. All SMG's use SMG ammo, all shotguns use shells etc... It is the gun itself that is elementally charged.
I think some of your building textures are a little busy, you may want to simplify them or make elements of the texture larger, it's kinda hard to read.
Almost all the cylindrical elements can benefit from this technique which will save you lots of tri's in this case: http://www.poopinmymouth.com/process/tips/examples/sphere_trisave.jpg
for the barrel, just have it as a sepperate overlapping element, that way itll be easier to animate, and you wont be using any extra polies (in fact youll be using less).
don't forget to release the buttons after edit the mesh (vertex, edge, border, polygon, element) before to select the skin modifier again. (sorry for the bad English)