Just listing the builds we have, maybe we can check for complementarity
I plan to main HA, as I've seen plenty of medic already
So certs are going that way, more toward a resist HA depending on nearby medics than a more self-sustained type (to be clear, I've gone Resist Shield + NanoWeave, which makes you more prone to lose health, but you'll lose less).
Main weapon GD22S, secondary EM6 (thanks to Alpha Squad). Spec AA rocket launcher
Secondary class is medic, I already upgraded to 2/3rd the medigun. Main weapon GR22 (thanks Alpha Squad again!), secondary NS11A. I don't plan to upgrade much further until my HA toon is more complete
Vehicles : AMS, Reaver (rockets), Lightning (HE gun), Lib (Zephyr AI/AV gun) for team vehicle. You probably won't see me in a Vanny, I hate it with a passion.