FNV puts hard enemies in areas they don't want you to go to yet. The theory being that you won't venture into them until you can safely fight those creatures. Giant radscorpions and high level gangs drop a pretty good hint that you shouldn't really be wandering north from goodsprings yet.
Giant radscorpians are imo a good balance it's mostly their DT that keeps them alive even a early character with a good weapon can go one on one with them back peddling imo..
It's the fact that bullet sponge's are back that's made me a bit gnarly, I got in a fight with some homing pigeon of a CL assassin group the leader of which took way more hits than I could take at twice his level.
My guns AP was high enough to get through without special ammo, but still it was like throwing sticks at him, that and running into reavers while sneaking a way off only to be auto spotted and run down.
So my point is the game is tactically challanging as it should be, but the one point everyone made on this forum way before release is that bullet sponge's are not needed at all.