There was a thing in Wolfenstein: Enemy Territory that wasn’t often thought about, but made a huge difference. Resource meters.
Using abilities would cost resources, much like the cooldown system we have now. Most maps had a second objective to fight over, the Command Post. Engineers could construct it to speed up the recovery of the resource meter, enemy covert ops/engineers could blow it up to allow an another engineer to claim it.
DB seems very lacking in tiebrakers, perhaps reintroducing such a buff/debuff could help level out current maps (Bridge), and be a little more enticing to play?
[spoiler]¹Splash Damage rocks your socks[/spoiler]