I guess I must too.
The main quest bosses are pretty tough as a Hunter & for non-expert FPS players, tho. After dying repeatedly w/no weapon taking more than a sliver of health off him, I had to use a very cheap tactic to take out Roid Rage dude and I'm not sure how I'm going to deal with the next one. Maybe if I level up to where the quest is grey...everything else has been a very nice, consistent solo challenge but not "impossible."
Typically, I do every quest that I get and leave anything that seems like it might be a "boss" one for last, and the bosses have generally been pretty easy. But yeah, I can see how it'd be difficult for a sniper character (that's what Hunters are, right?). I highly recommend a good SMG or full-automatic machinegun as a side weapon, or some kind of caustic shotgun for armored enemies like Sledge.
I wound up playing as a Soldier, and I avoided any skills that boosted any particular weapons, just because I like to try anything interesting that pops up. Seems to be working well so far. I'll try one of the other classes when I hit 50, I guess.
Also, there's an INI file you can edit to give yourself as many inventory slots as you want. I forget which file it is, but it should be an easy google. I upped my backpack to 100 slots and enjoy the game a lot more now. Just pick up everything I see and sell anything that's green or white without looking at it. I'm almost at the cash max now (it's pretty rare that I find anything I actually want to buy now).