They just put out an update this week that gave Gibraltar and Caustic (the two fat guys) an extra passive ability where they take 10% less damage. Also, Gibraltar's gun shield now absorbs more damage. That helps those guys out so they don't feel like such big targets that die quickly. And then last month or so they updated the hitboxes. That made Pathfinder a much more viable option.
I still play just about every day for 2 or 3 matches. My favorite is definitely Lifeline, but I can play with them all except for probably Caustic, I just don't find him enjoyable at all. They did just make his gas more potent, so maybe I need to give him another shot. Really though, you can win with any character. I almost exclusively play with randoms and I usually win at least once every couple of days, and usually I'm in the top 3 squads if I can make it through the first couple of minutes after landing.