I don't know if any of y'all have played the game Planetside (a MMO sci-fi, 3-sided, twitch game). However, it'll give you a completely new perspective on horde gaming (they call it a Zerg). Try holding a doorway with 30 guys in heavy power armor, plus attendent engineers (armor repair) & medics, spamming thousands of grenades around the corner at the unending tide of 100+ guys coming to kill you in the most violent fashion available.
Aside from the laggy, uber-killfest it represents, there are a few features with merit, and could merit some looking into as possible MA "solutions".
* Experience system: You gain by killing & capturing, just like any other game. There are 20 levels. The more levels you get, the more specialities & implants are available, giving you a bigger weapon selection, vehicle access, better armor, etc. In addition to this, there is command experience. To gain command experience, you must be leading a squad of 2 - 9 people. It's much like being on frequency in AH, except you get health bars & each player is #'d on your map. You only get command exp. points when your squad is involved, determined by proximity & length of stay, in the capturing of an enemy facility. You do not get normal experience points in command mode. Bear with me here guys, I do have a point.
What the benefits of command mode are, as you level through it (from 0 to 5) you get expanded communications. It's heirarchy of private comm channels, from the 5s on top, down to the 1s. The command rank (CR) 5 players tend to direct the hordes and get land grabbed. The higher CR also opens up an even more impressive arsenal including emp strikes (3), small orbital strikes (4), and the massive orbital strike (5). It allows the high command rank players to more signifigantly impact the battlefield itself, helping to drive their troops forward. Overall, it give the horde a purpose and motivation, keeping it moving towards the endless series of objectives (just like MA hordes, but with more focused guiding intelligence... mobile spawns help too).
The second major feature is called "PopLock". Each of the 3 sides have a permantely safe home base. All of the battlefields are on individual islands you have to teleport to. Each side is only allowed so many people per island (game balance/server load issues). Once an Island fills for your side, the population lock kicks in, forcing people to other fronts, or making them wait in line to catch up with friends. It helps keep the fights going all over the place by enforcing a balanced disposition of forces. In other words, it encourages hordes to meet headlong and slug it out, while other more specialized teams (who hate the laggy Zergs) basically turn into commandos, pick their own fights, or cause so much chaos a Zerg forms just to fight them.