Early game could be tough on survival, no doubt. But with power armor and the right perks (more damage, life giver last rank, damage resistance, gun nut and science), it's just a little more time consuming to kill enemies. Fast enemies might be able to get to melee range, but that's what shotguns are for.
The game is no harder than any previous bethesdas games. If you truly want difficulty, then dead-is-dead is the way to go. Adds a lot of athmosphere when you know even the slightest miscalculation will cost you your character.
Apparently melee is very powerful, even more so than guns, since they stagger enemies. Indeed, I can verify that statement myself. Had a pretty tough legendary glowing one to fight that kept resurrecting his friends when I was trying to circle and shoot hit. Died, switched tactics by taking my only melee weapon into use (an electric baton, I think?). With strength 2 and no perk points into melee, I was able to kill the glowing one by spamming attack.... He had no chance to resurrect his friends when stun-locked. GG