Can't answer all the questions but have comments on a few...
Matchmaking - can't see this having a big impact. I'm in the UK and have had a few (probably around 10) with people in USA and the lag was terrible. That will no longer happen? Err yes, because I use "any" as it returns better quality matches overall than Best.
The increase in health to the Dragonfire is a pain for me personally, (and probably others), as I have still to complete the destroy 10 of them with launchers. On the FHJ I am up to 7 out of the 10 and they were a case of waiting for them to appear then switching to the class with the FHJ and then getting a shot on target (not always easy with the Dragonfire movement), but I managed the 7. Just played a match and Dragonfire gets called in, out comes the FHJ. Two shots, both on target, Dragonfire still flying about, somebody else shots it down.
This highlights a problem I have with all these buffs and nerfs - they make it unfair on people who have not completed certain challenges. I'm done with the FAL, all maxed out on it, and glad because those who haven't will have a harder time doing it now. But I haven't done the SMR and I will have an easier time doing it than those who already have did. I guess it's all swings and roundabouts, but it still irritates me.
Disappointed more hasn't been done to improve matchmaking; one of the biggest factors in all the lag and lag compensation issues, and the single most important aspect in actually finding the game enjoyable or not.