Arguably, quick is really the only positive trait you “need”, because it’s 10 speed that you would otherwise have to drug up for, stacks on top of said drugs, and applies to both moving and actions. Even without fleet footed, a hit of Adderall combined with Quick gives you somewhere between 130 and 140 speed, which allows you to outrun almost anything. Quick also serves to dampen the speed penalties of pain and overburdened (or cold, painkillers, etc), allowing a damaged or weighed-down character to fight for longer, or escape more easily. I also hate seeing speed in red, so it’s a personal thing.
NPCs I can’t recommend enabling. The two times I’ve created worlds with random NPCs, they crashed my game at some point. You also can’t count on the shelter NPC being able to teach you martial arts as a means to bypass the 3 point investment in martial arts. I attempted this and crashed every time I tried to have him teach me ninjutsu. Sometimes they start with inappropriate equipment, too. I recall starting a game and killing a shelter NPC, who had on him a fusion rifle as well as the charge rifle. Another game, I started in an evac shelter that managed to be located downtown in a major city, surrounded by zombies, brutes, a master zombie, and the zombie dogs that master zombie created to later run me down and kill me. The NPC wielded a CBM: Time Dilation and ran into the fray. I just stared. He didn’t survive long.
In general it feels to me that the difficulty of the game is inversely proportional to how many points you invest in the strength stat. Strength is vital for almost every playstyle. The most effective martial art I’ve used so far is taekwondo. It’s a slow start to get the blocks unless you find 101 Wrestling Moves, but with a character touting 14 or 15 strength, your blocks will make 63-70% of the blow’s damage magically disappear, before armor mitigation comes into play. With arm guards and leg guards, a player could tank most of the melee mobs in the game without any trouble, as the damage to the arms and legs will often be negligible. It let me tank two Zombie brutes in the street side by side with no problem, so it should serve in the majority of situations, except when dealing with ranged opponents, which at the moment are a rather small portion of the total population.
And of course, there’s always cars.
Other tricks to try if you aren’t doing them already are wearing fitted sneakers and crafting yourself long underwear to wear. With those two your feet and legs will be at -1 encumbrance, dropping your movement cost. Glove liners also give a -1, but hands don’t seem to be capable of getting -1 encumbrance. It still lets you wear 1 encumbrance gloves or gauntlets without taking a penalty to encumbrance, however. Wearing two fitted tank tops and two fitted underarmors will, in addition to making rain no longer bother you, give you -2 torso encumbrance, which is effectively +2 to melee and dodge as well as -40 to melee cost. In addition to providing that boon, it allows you to wear one rucksack or two backpacks and avoid being encumbered at all in the torso region, making meleeing while wearing them more feasible. Soft arm guards, should you find them, will serve in keeping your arms warm, should you need to use ranged weapons.