I'm loving this version of battlefield. I prefer an older time setting. Not much of a fan of heat seeking this, infra red sights this, night vision etc. Feels much rawer with the WW1/2 settings.
I play medic a lot too, and I cant say I've ever had the mix up with gas mask / needle bug though.
With regards to medics not reviving. It could be due to the fact they've swapped the needle gadget with a rifle grenade of some sort
Got a deal for an Elite controller and BF1 for £124.99. Heard good things about the controller, needed a second anyway and wanted BF1 so a good deal all round. 
Reading around people are reporting that class levels have dropped and the old class you were was bugged and not correct, checking I see my medic has dropped from mid level 8 to just under level 5.
looks like theyve added squads to the pre game screen too still trying to figure it out mind.
how do you rank your classes up quick?
Some do, some don't. I am bloody loving it.
This smashes BF4 out the park for me, finding it incredible.