Regenerated my pilot for the first time - I hadn't spent a single credit and instead just tried out everything as it unlocked. I had enough to almost buy my entire kit back including Low Profile. But I find it a little strange that factions don't stay unlocked.
The loadout I've settled on:
Devotion - Extra ammo, faster aim down sights, stock sights (I prefer the wider FOV to pick up secondary targets)
Thunderbolt - I only use it because it gives you a ton of Titan charge.
Firestar - see above. Nice for killing grunts too I guess.
Pulse Blade - Interacts with Devotion very well. If I'm not taken by surprise I'm confident I can win most exchanges and this helps that happen. The fun part is using it to see through smoke in bounty hunt/attrition and mowing down everything. I got a triple pilot kill on Crash Site and had enough in the magazine left to kill some grunts too. I was using the threat highlight scope on the gun for a while but I don't like how much it obstructs my view. Stock sights all the way.
Titan is Northstar - enhanced payload and extra dash. I dabbled in Tone and Scorch but I do so much better on Northstar. As fragile as she is, her slim profile and agility lets me escape so much shit that I tend to go on insane streaks. With good ally support I tend to just completely take apart the other team. Tether still sucks and flight mode is very situational but I've definitely been learning when to use it to pick off a fleeing pilot or get a view of the battle. But the ability I really slept on was Northstar's fire rocket thing. With enhanced payload you can do all kinds of stuff with it - clear out an entire drop pod of grunts, kill pilots hiding in buildings, or even get things off your back without needing to pop smoke. It also does a shit ton of damage to slow titans like Legion. I get a shocking number of kills with it.
Boost - extra battery. I actually give the battery away quite often just to get my own titan out faster. Northstar benefits from it greatly if I do decide to keep it.
I could see myself experimenting more but really this is what works for me. I tend to do very well even though this game likes to throw its patented bullshit bad respawns at me.