So, what - a full two months since any kind of meaningful update? I think that's a new record for me. I've been really busy and haven't had time to touch on this, but I mean to get this out relatively soon. Here's what I've taken your suggestions and done with them:
I added a couple new troopers - a grenadier class and a commander class. The grenadier has the weapon requested by Kinetosimpetus (although I scaled it up to make it work as a launcher-type model) and one of those water-tube guns instead of a squirt pistol. The commander has a gun that required a backpack because there are only so many ways I can make the board shorts model different with accessories:
Most of the time has been spend working on new game modes, though (as indicated earlier). There are four modes that the mod will have: Team DM, Survival, Sand Castles, and Soak the Wookiee. Team DM is fairly self-explanatory, and it's there just as a plain-vanilla mode.
Survival Mode
I knew that I wanted to have a mode with some kind of leveling feature, and you all know how much I like my wave modes. What I did here is make a singleplayer mode that combines both of these concepts. Survival mode is based around facing waves of enemies increasing in number and difficulty. Allow me to clarify - AI can't be made "smarter" or "more difficult," but what I did do was make them do more damage as the waves go on. They also become more and more focused on you as a target as the waves progress (a gradual shift from a "deathmatch" to "destroy" goal).
Survival mode also has several ways to improve your character. There's a simple level-up system - as you defeat more enemies, you gain experience. As you hit levels, you gain health. You can also increase the potency of your weapons - you start off with two very basic weapons and some water balloons, but as you use your weapons more, you can "level up" that weapon to better weapons. You can also gain other weapons during the course of the match.
Sand Castles
Sand Castles is a pretty straightforward conquest variant. Each team has a sand castle located at one of their CPs, and that CP is uncaptureable for the majority of the match. Once a team's reinforcements have been drained low enough, their sand castle becomes vulnerable. A victory by either reinforcement drain or by conquest is impossible until the sand castle is destroyed - after a sand castle is destroyed, that team's final CP is open to capture and their remaining reinforcements can be drained/killed. Additionally, any unlockable units are unavailable to the human players unless they own a majority of the CPs.
Soak the Wookiee
Conceptually, I think this is my favorite mode (although technically it pales to Survival). This is another conquest variant, although no one on any team can capture CPs. The idea here is that there's a Wookiee wandering around the battlefield, and whoever soaks him the most at any given time will force him towards the opponent's CPs. If you've soaked him enough, he'll capture posts for your team, but if the enemy soaks him enough on the way there, he'll turn around and capture for their team. The match plays like a tug-of-war for control of the Wookiee.
And here's a picture that has no relevance to any of these modes: