This is pretty much GW1’s Fort Aspenwood except it’s basically 2-3 FA game in 1 if translating this to rush mode. FA is a competitive mission in GW1’s 2nd expansion so if we were to have FA again in GW2, we’d either have to wait for GW2’s expansion or have the same kind of gameplay mechanics with now maybe Hyleks vs Kraits?
I’d imagine it would not be hard for Anet to implement rush mode/FA but GW1 had FA already where GW2 takes place 250 years from GW1 so the game modes will have to adjust to how the lore of the Luxons(attackers) and Kurzicks(defenders) fare after 250 years. By the end of GW1: Faction, the 2 factions joined forces to defeat Shiro so having luxons fight kurzicks again in GW2 will probably not make sense.
I personally would love to have FA again in GW2 since it’s was popular even before GW2 launched. It was casual friendly as well since sometimes it’d only take 1 or 2 key player(s) to finish the objective of the game. There was emphasis on team work but it wasn’t critical like WvW (where a single player would not make a difference) but it was balanced enough for you to play alone.