If you are dying to Proxies suiciding into you/a group that means you aren’t reacting properly. The mine throwing/shooting proxies are the easiest to take out. If you see one running in with no gun out just shoot them. If you fail to shoot them simply long jump away (press crouch and then jump and you do a long jump) and then proceed to nuke them in the head while they are busy trying to switch weapons to shoot the mine.
That style of proxy is done as a gimmick or for laughs…but it’s not consistently effective against players who know how to easily beat it. Her mines are a bit ridiculous right now when placed in some spots on maps and that should be addressed. But other than that she’s fairly underwhelming once you your feet on firmer ground in understanding the games mechanics.
No, loadout cards like Silver, Gold and Cobalt or special edition cards do not give any extra power nor should they (this is not a pay to win game). Every single merc had, up until recently, only 9 cards (generation 1 set) and they were static. So no matter which rarity of card you got they were one of those 9 cards. Generation 2 loadouts are going live today I think so there are now more cards to choose from but no extra weapons.
As others pointed out giving Aura access to AR’s and things like that would throw the balance out of wack as each merc is not only balanced with their hp, their ability set and their speed but also with the weapons they have access to. A lot of people, including myself, would like more choice but right now that is not in the cards (pun definitely intended) 
And Fletcher is getting a slight nerf to his AoE damage in the new patch but his direct sticks aren’t changing. When fighting a good Fletcher or even a bad one just remember to not chase. Also, long jumps and randomized movement is your friend. You might feel like an idiot while doing it and it won’t feel natural but it throws the off pretty often and then you end up consistently gunning down Fletcher’s who rely too heavily on them.
Rhino is super weak once you know how to fight him. You know a Rhino is sitting in a door? Don’t enter that door. Rhino’s weakness is making him come to you due to limited range and spin-up time. And if he’s one of those Rhino’s who constantly holds M2 to spin up you ALWAYS know where he’s at due to the audio which makes him even easier to kill. He’s OK in some defensive situations but that’s what explosives mercs are for. Fragger, Nader and Fletcher tear him up and even Thunder can drop him pretty if you get a flash.
Dome has been a pain point for some people I know. I know Splash Damage has a relatively new person going through and trying to fix issues like what Dome has so that might get alleviated a bit in the future. Also, as others said, you can set your settings to low which is pretty good but you can also get an fps config that can take some settings even lower. This can help FPS dramatically on some systems. Also, the game is heavily CPU dependent since it’s a Unreal Engine 3 game so if you have a weaker CPU you’re going to run into some FPS issues. And a lot of people end up running into heat related issues because most games don’t push their old CPU’s as hard and suddenly start getting super low or stuttering FPS in DB due to it.
