We use 6 basic attributes:
Endurance = determines maximum health, max stamina (combined with STR)
Strength = determines max. carry weight, melee dmg, max stamina (combined with END), used for bully check in RPG
Agility = determines max movement AP, interrupt chances and evasion in melee
Dexterity = determines AP for using items, melee CtH
Marksmanship = determines ranged aim accuracy
Intelligence = determines progression speed of all attributes, used for INT checks in RPG
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There's a special affiliation "perk", the faction. All encountered NPCs except the player have an allegiance to one of the 3 major factions; this is part of their story and used as check in RPG
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Certain specialization/perks below require Str/Dex/Agi/Mrk levels above 75. Atm we're tracking the following events for specialization progression (list is subject to change, it's still WIP, so I am not going to go into details/bonus/malus yet but if you feel like something vital is missing, feel free to mention it):
RANGED
- close range attacks with handguns/shotguns
- medium range attacks with rifles/crossbows
- long range attacks with sniper rifles
- headshots
- burst fire attacks
- attacks from higher ground
MELEE
- blade/pierce attacks
- blunt attacks
- hand to hand attacks
- heavy melee attacks
UTILITY
- carrying weights encumbered
- using medical stuff
- using grenades
- backpack crafting
SPECIAL
- virus immunity (player's avatar)
- barter expert
- drone pilot
- stealthy
- field exp. vs zombies
- field exp. vs human enemies
You can build stealth ranged, stealth melee, CQB, snipers or h2h characters, medics, grenadiers, mechanics and other mixed flavours (such as INT/STR interrogator). You get one preset perk from the recruit's backstory and you can train as many others as you want. When you assemble the team, you choose each member's secondary role from the list of perks known. So you can have two "running" perks at once.
We are not going full RPG character customization and never will, especially with purely non-combat stuff. We feel the above support the scope of the game, since it's first and foremost a turn-based strategy. Same with base building, we're not going to have another Banished/Manor Lords inside the walls of the shelter. As long as the RPG and the survival stuff enhance the experience & immersion of the player we're happy.