Things really opened up for me when I was able to get a decent automatic at 16, I believe it was. I definitely think melee has it's place in killing some of the real low level bots, I'd not want to waste the cash for ammo to kill the easier ones, but there are also some pre-level 30 things I'd not want to use melee on. The area north of the forest, the road I believe it is, is a good example of this. It was one of the first areas where a robot was shooting back at me with a gun and it was either hit it at range, which requires at least the MP5 or take unpleasant amounts of damage. Once your defense is high enough, you can basically just stand there and let them shoot at you, but at pre-level 30, not so much.
Another thing that seems to be not so great is the amount of cash you make from kills, compared to that which you spend to replenish ammo you use for XPing. it might be that there's better weapons to use that allow for less shots per NPC, the shotgun might be an example of this at level 40, but with no real documentation on how the weapons differ from one another, it's difficult to figure out. I honestly figured that this would improve, the higher I got, but even at level 80 now, making cash sucks the big one. Even a friend of mine who's 140 or so says roughly the same thing, which I find to be a little disappointing. Oh, yeah, and this silly bs where explosions from player's rockets and grenades killing you? Apparently this seems to be quite common in certain areas, where people will spamkill lower level players with the grenade launcher, which is a little silly. it does make for a nice quick trip back to the safe zone though.
Only my opinion, but if explosions are going to effect players, shouldn't bullets fired from players do the same thing? With the lag we often see on the server, the bullets taking seconds to hit a target, lets have a matrix-style sound so we can hear them coming so we can dodge them. lol
Not sure if it's me, but I'd love to go Kung Fu spank ass on some robots too.
Ah well, one can always dream.
Take care.