Siege is an asymmetric multiplayer game which manages to take a common bugbear of online shooters - camping - and turn it into a valid mechanic. There's more to that than simply one team being defenders, and therefore having a good reason to stay in place. Lots of games have a defending team. On hostage rescue maps, Counter-Strike's terrorists are defenders and sticking to their entrenched positions makes perfect sense, but it's also infuriating for the attackers, boring for the defenders, and derided by nearly everyone on public servers.
By introducing the ability to reinforce walls and entrance points, and giving everyone the ability to shoot through unprotected floors and walls, camping becomes much more interesting. There's a more complex series of decisions being made by the defenders who decide to stay put, as they choose which angles to defend, where to drop their barbed wire, and where they're safest from an invading player who decides to take a punt at shooting through a flimsy wall to see if someone is on the other side.
Many of these tactics carry over to the game's cooperative Terrorist Hunt mode, whether you're attacking or defending, thanks to AI that's good enough to mimic a decent opponent. This mode's suicide bombers are the one exception.
These hazmat-suited characters shoot at you, take more bullets than normal to go down, and self-detonate if they get close. This occasionally leads to dramatic situations as bombers crash through walls like a Left 4 Dead monster and force you and your friends into retreat. But just as often you'll be carefully, tactically moving through the cramped spaces of a suburban home when a bomber will round a corner not three feet away from you. They'll explode before you have the chance to react and they'll kill you instantly. It is a shit way to die.
You can hear the bombers from some distance, which lets you know that they're coming. You can scout buildings in advance using a remote control camera, letting you mark them on your HUD in the same-coloured HUD icon as all other enemies. At times, I can see why you'd want a non-standard enemy type like them, to change the flow of a fight, introduce extra tension, create a moving obstacle that must be accounted for. But the Bombers are a bad version of all those things.
The issue is that there are no interesting options for dealing with them. Either you're far away enough to put a bunch of bullets into them before they reach you, or they're so close by when you first see them that you're dead before you've fired a shot. If you're defending, then you can arguably drop barbed wire to slow them down, but that's what you do anyway, and if you're attacking then that option is unavailable to you.
Perhaps there is a specialist I can unlock after hours of grind that will help me deal with these units, but even a hard counter that negates them wouldn't make them fun. They seem almost thoughtless, in so far as I can't discern what behaviors they are there to encourage or discourage in players.
If I were to redesign them, I might make it so that they grab and restrain players they come close to rather than instantly exploding. This would then trigger an explosive countdown that would kill that player unless another person could get there in time to shoot and kill the enemy Bomber. This would still create moments of drama as they lunged towards you in close quarters, but it would also create an additional moment of tension while players rushed to the aid of their struggling teammate. It would encourage teams to stick together. And it has precedent in the game since, if you're shot to the ground, there is a similar time limit during which a teammate can reach and revive you before you bleed out and die entirely. This is essentially no different than how Left 4 Dead's Hunter or Smoker works, but stealing from Left 4 Dead never seems like a bad thing.
Alternatively: I'd just take them out. They feel unnecessary in a game that's otherwise efficient. I hate them.