I have recently setup my class around a defensively oriented playstyle. I run full support (Night Owl, Squad Mate, Oracle) and a class designed to allow me to secretly stalk about (Honey Badger, OTG, Incog, Ping, Takedown).
This setup has drastically improved my game but that's not the best part. This class, though incredibly defensive in principle and nature, has allowed me to become incredibly aggressive. I'm now averaging 30-40+ kills per game in DOM matches. AVERAGING. On top of that my deaths have been cut in half. Because I'm so attack oriented now I dictate the spawns and I control the matches rather than the opposite. I've attracted the attention of others and last night in two separate lobbies I received some wonderful hate-mail.
I'm wondering way more players don't go with Support. I find it to be a great way to cover all your bases and judging by loadouts in Final Killcams and Killcams everyone thinks Specialist is the way to go.
You haven't seen my loadouts for clan wars yet but when I'm playing clan wars, all I run is Support. And its for the very reason that you mention. I can be ultra aggressive and the streaks that I run are designed to knock out the enemy defenses. I tend to run MAAWS, Squad Mate, Ground Jammer, Oracle. Obviously I can't run all 4 at a time but I mix them up with only the Oracle being a staple. Which ones I use depends mainly on what the enemy is using and the game mode. If I get on a good run, I can cycle these streaks 2 or 3 times in a match easily. The best part is I'm not the only one running them. So if we get matched against a team that for whatever reason doesn't run blind eye, it can turn into a real slaughter fest quickly with back to back to back Oracles. It surprises me that I don't see more Support running during clan wars but then again a good portion of the community is stuck on running Assault or Specialist all the time. Their folly is my reward.
If you have 3 or more people on a team and are playing DOM or KC, if you all run support with a squad mate you will clean house. You can always take the flag and pick-up tags. It is a huge difference. Most people don't use support because they think it will benefit them. I started running the squad mate when I was playing DOM solo just so I knew I would have help when trying to cap flags since so many people like to sit in the corner and not play the objective.