Seriously great job, Divine. :)
/prostrate.
I haven't been ingame for some time, but still will try to help too.
Fixer :
Ring of Putrescent Flesh
Ring of Sister Pestilence
Quite useful DoTs against Fixers. 2 seconds to fire them of. Just don't know if the Alb one can be launched without attacking, which is required if you want to do it while running - supposing you are chasing the kiting fixer. That is how I remember this. Correct me if I'm wrong here, please.
Alb ring requires to be worn, but the 0.1 equip time makes this disadvantage not a big deal.
Engineer :
What I have done was killing the dog with just regular hits and dimach, which could be wasted due to no use against engineer. Haven't tried debuffing init of Widowmaker, but I think 1-2 second of additional delay isn't that much, so it may be worth it.
Nano Technician :
You forgot to mention Red Dusk and Incapacitate. Using both at the same time definately will slow them down making kiting much more uneficient.
Same goes for Enforcers, the NanoC Init Debuff will seriously make their casting hard - this means no absorbs and much easier way to get their huge hp down.
Enigma + Alb ring could be usefull too for eating their nano.
Soldiers:
Generally it works much better in mass pvp then in duels. Stun, Init Debuff at the very beginning and eat them alive! :) Used it very often and almost always succed. In duels Ape + Brawl may be a good start and if the soldier hasn't used AMS and addidtionaly is stuned, follow up with BBCS.
As for some general tips, I would add : set up your GUI correctly! Have a clear view of your opponent. Seeing
Hear me Immortal One! over doc should make you hold on with your alpha or
Mongo Rage! over reaver profession should make you ready for their gank. It can be seen even if blind runs, so I find it really important.