I really like this idea, and can see 2-3 maps coming out of it;
Civilian-Based Insurgency;
Location: Iraq, Basrah
A Base in a Muttrah v2-esque (big, urban) map, with a British base in the middle. The map starts with the base under attack (C-spawns all over the city), the British have LMG positions and towers all over their walls (same type as the VCP on Al Bas). This base has multiple entrances and a large gap between the outer wall and a smaller inner wall (one-row high/deep those large sandbags. Each entrance has a standard Bunker in its vicinity, which has several spawn points tied to it at that entrance (not just the one on itself). Once the bunker is destroyed, the INS. gain the advantage there and start to capture the flag (Bunker destruction is a prerequisite to flag cap). Once the flag is captured, the gain a couple of LMGs on the small inner wall.
Inside the inner wall is a complex of tents, wooden barracks blocks and administration buildings, which have British RPs spawn randomly at the start of the game. The main Admin building contains in it's basement a Bunker which must be destroyed before the building can be capped. There is only one AAS element to the INS. Attack in that they must cature one of 4-5 entrances before proceeding to the Admin building. At the start, the INS. have unlimited tickets, and the Brits have around 300. The Brits have NO requestable kits and must rely on standard kits until reinforcements arrive.
When the Counterattack begins, the Brits gain unconditional spawn points on 2-3 helipads (preferably a static Chinook spawning there as cover) and are granted 300 extra tickets, intel on 2-3 caches and the INS. lose all spawn points within 1 square of the base wall. The Brits also gain access to their limited kits. The ma then plays out similar to Al Bas, with the British main becoming uncapturable and all entrances gaining unconditional spawns.
Militia Based, reversing CA
Location: Afghanistan, edge of the green zone
[This map is based around a British FOB that I can't remember the name of; it was in Ross Kemp in 'Stan, and was literally right on the edge of a deserted town]
The base is under attack from the beginning, with a Militia main base in the lush green zone (tunnels if possible) and several strongholds inside the town.
The British begin with their sole spawn in the FOB, moving out through the town securing each stronghold while the Militia fall back into the tree line and eventually into their main base with many spawn points and hidden entrances.
After their reinforcements arrive, the Militia begin their counterattack, and the Brits lose their reinforcements (The Militia are considered to have brought down several Chinooks on approach to the base, which means British reinforcements are cut off). The Brits then have to hastily dig into what positions they have taken and hold off the Militia attack. Every hour the attackers and defenders will be switched.
This could be a *VERY* long map, with the attackers receiving a boost in tickets when their attack begins. The only way for either side to win would be to crush their opposition through kills or captures.
/essay
I don't think it's a hijack, just an addition

I do quite like this possibility.