Dear Devs,
After watching the devtalk for a bit, an idea i had to deal with the frontline would be to make it an actual frontline combat mode. A game mode where the attackers want to push the enemy defensive lines back and the defenders want to fortify and defend their locations.
This will also make support a very valuable class to play in these modes, focusing on defensive gameplay
As the attackers, your job is to be on the point and deal some sort of ticking damage to the defending objective. By being there, by destroying buildings etc. This would allow the attackers to have any effort put in be rewarded instead of being stonewalled by the enemy having +1 guy.
This would also give a lot of value to the fortifications built by the defenders. Allowing them to fortify the point and re-establishing the frontline again and taking full control of the buildings/objectives.
When a frontline completely falls. Give the defenders a small amount of time (say a minute) to fortify the next line of objectives after.
This would give the gamemode more flow and a natural cadence of the enemies trying to demolish your fortifications and give value to more classes