How will melee combat work (considering it probably can't be worked out like the firearm solution)? Damage depending on skill instead of different sized crosshairs as for the ranged feat?

At higher skill levels of Melee (and Brawl), you’ll be doing more damage. To make the Melee/Brawl experience more visceral, we’ve also added combos that are accessed by the direction keys. A higher Brawl also makes it easier to aggressively feed in combat.
To be more specific about the unarmed combat system, hits, misses, and damage are all keyed off of the interaction between the melee feat and the defender’s defense feat (and soak, if applicable). The results of that interaction will determine whether the NPC will dodge, block, get staggered, or any other number of possible outcomes. It’s not entirely data driven, however, as the player has to decide in real time which attacks or combos to use and on which enemies (as you are often fighting multiple attackers). The attacks and combos are keyed off the different direction buttons. Holding down “W” (moving forward) will key off a different set of attacks than holding down ”A” (left strafe) will.