I suppose I'm mostly Engineer, since that seemed to make sense when piloting. If I decide to try to mix it up more directly, say because my base is being overrun, I tend to go Light Assault. I think I have the best luck with that gun, I might win 25% of my fights, but I think that's the one that obscures the entire target picture with muzzle flash. I have to stop firing to check if the other guy is still in front of me. After I get tired of constantly dying, and if I cant spawn a vehicle, I'll play as an Infiltrator. I live longer that way, mostly because I'm skulking around in the hills.
Yeah I play engineer when I'm driving stuff, but unless I've got a squadmate MAX or three to heal I never willingly use it in a combat situation. The gun it comes with is still pretty decent, I can get kills with nothing but the 2x sight but I try not to get in straight up fights with anyone on my way to get back in a vehicle.
The idea behind Light Assault is to never be in a situation where the other guy knows you're gonna shoot him. I hardly ever play it but when I do, I unleash my inner chimpanzee and jump around the rafters/trees/roofs of a Biolab on defense.
For vehicles I love the wide blast area main gun (supernova VPC) for the Magrider combined with infrared. That gun makes you more vulnerable to enemy tanks, but NC/TR hate their tanks and a Magrider still has the advantage solo as long as you can Magboost behind him and shoot him in the back. 100 certs for the Magbooster though, and it has a loooong cooldown unless you spend tons on it like me. But yeah, IR lets you instantly spot all those little squishy ants hiding in rocks and obliterate them before they can kill your tank with rockets or C4.
Similarly, I have the high explosive main gun for Lightnings and it actually made me enjoy playing a Lightning. Although you still go down easily, at least you can kill things and it's one 'big' shot rather than the annoying default gun.
I'll look into those upgrades for the LMG. The foregrip reduces recoil/muzzle-climb, I assume? I'm surprised scopes work with all the muzzle flash, but if they do, that sounds like a winner, too.
Foregrip is really useful for strafing while firing. Which you should be doing. I don't really have problems with muzzle flash, I use 1x and 2x sights.
I like how you say, "The Crown, (of course)". I have no frigging idea where or what the Crown is. : ) I'll poke around on the map. Are we talking about a particular continent here, or are all of those places common to all "maps"?
Specific places. You'll frequently see those areas show up on 'instant action' but The Crown is right in the center of Indar. It almost ALWAYS has people fighting over it, and while it sucks to assault it, when your team has it you can rack up tons of kills defending it as anything you'd like. As an Engineer there are almost always some antiair MAXes hanging around and those are EXP goldmines if you can get into their squad (you get more for healing/resupplying squadmates). Combine that with double XP coming up in a few days and you'd be rolling in it.
Mani Biolab is on Esamir (Northern area) and for some reason it's always being attacked on my server (Soltech), and us Vanu are always defending it fiercely. I like the base layout and it's fun to defend. Plus it was the very first place I was dropped when I first tried the game so it's kind of like home.
Likewise on my server the NC love Tawrich Techplant (Indar, bottom right) and that place is ideal for tank vs infantry combat in my experience.
Of course, your mileage may vary but the heavily contested areas will almost always be listed in Instant Action. You can get a rough estimate of how many enemies are there by clicking on the tile...'enemy platoons detected' means there's a
lot of dudes. Oh, and remember that you can steer your drop pod and end up in weird places. I like to land on top of main buildings so I can hopefully get the drop on some snipers or turretnerds, but often there are some LAs hanging around hoping for people to do just that.