Perk balancing suggestion:A lot of perks, like Infiltrator, Animal Tracking, Lockpicking, etc. are really underpowered and take way too many valuable perk points to get anywhere useful. My suggestion is to compress the perks into only 3/4 ranks rather than the default 5, and to add better unique rewards, comparable or equal to a magazine or rare item (the fact that certain magazines like the mine immunity one almost COMPLETELY obviate an entire 5 point perk tree is absurd).
For example:
Animal Tracking 1: all small animals (rabbits, chickens, snakes, etc.)
Animal Tracking 2: all large animals (boars, deer, etc.), 25m range boost
Animal Tracking 3: all predators (wolves, dingos, bears, etc.), 50m range boost
Infiltrator 1: 1s extra floor time, 25% mine and spike damage reduction
Infiltrator 2: 1.5s extra floor time, 50% mine and spike damage reduction, not slowed by traps
Infiltrator 3: 2s extra floor time, mine immunity/pickup and 75% spike damage reduction
Lockpicking 1: craft lockpicks, 15% better lockpick chance and speed
Lockpicking 2: 30% better lockpick chance and speed
Lockpicking 3: 50% better lockpick chance and speed, chance to not break a lockpick when you fail
Cardio 1: 15% better stamina usage
Cardio 2: 30% better stamina usage, 5% run speed boost
Cardio 3: 50% better stamina usage, 10% run speed boost
These are just ideas off the top of my head, but I feel like compressing certain 'minor', underpowered perk trees would have people actually pick them, cause they're REALLY lame right now. Why get the teensiest boost to some really minor skill when you could get tons of weapon boosts or an important tech tree unlock? This might be easier than entirely scrapping/replacing admittedly cool, unique trees that just need some love rather than replacement.