FOG OF WAR
This idea depends upon whether or not sight-distance can be controlled server-side.
Mods place all AI on the map for this Invade and Annex mission- some in defensive positions, some on patrol. Sight distance is reduced map-wide to 100 or even 50 meters. Enemy positions could be map-displayed as usual, or for a bit more tension and excitement, display no icons.
This mission eliminates the get-on-high-ground-and duck-shoot methods we all use much of the time. This is down-and-dirty dig-em-out warfare that would encourage the support of team-style play. Could make for some really intense play.