GURPS PC 'roles'- a thought on pen and paper role playing in general

[starslayer]

I have been giving this some thought, trying to distill down the 'essence' of pen and paper role playing. I know this has been attempted in books like Action, role 1 and 2 below are basically what the threat value from pyramid are built to quantify, but I'd like to stay away from that level of quantification.

Thus, I present the RPG character 'role' list (I have listed sub roles, but only the top level role is really important, the sub roles are just different ways to express that):

1. Murder- the ability to kill stuff
   1. Ranged murder - sniping, shooting, rocket launching
      1. Direct engagement (They can shoot back)
      2. Indirect engagement (they can't shoot back)
   2. Close up murder
      1. Direct engagement (Sword+board, sword, spear, etc.) From Minuteman37
      2. High mobility
      3. Area denial (IE- large area attacks, area of effects, toxic ground, emanations, etc).
2. 2. Survival- The ability to not be killed
   1. Durability- You can take the hits
   2. Avoidance - You don't get hit in the first place
   3. Blocking - You put things in the way of getting hit (Walls, etc)
3. Support- Healing, fixing, buffing, etc
   1. Aggro- If your a tank or otherwise able to take the hits being able to force foes to target you is excellent support.
   2. Fixing - You can repair/build THINGS
   3. Healing- You can repair PEOPLE (or PCs if they are themselves machines)
   4. Buffing/debuffing - you can boost the party or bestow penalties on the opposition
4. Problem solve- The ability to track down problems, follow clues, build stuff, and find a solution
   1. Mundane- you have great detective skills.
   2. Build/use - you can either build neat things, or have access to high tech gear and can use it to get information/solve problems
   3. Mystical - You have access to problem solving magic- seeker and analyze type spells, or things like psycometry
   4. Mental - You have mental dominance that can solve problems (mind reading, mind probe)
5. 5. Social interaction - The ability to win friends and influence people.
   1. Wealth- a little grease goes a long way to convincing people to do things
   2. Status- You have the power of your station which can move people
   3. Swaying - You can convince people about things/to do things

These roles have a tendency to pull your points in different directions. Notably there are MANY ways to achieve compotency in a given role. A psi with reliable easy to use mind control achieves the murder role, and the social and problem solving roles (sometimes everything IS a nail when you have a hammer). Notably being a standard or RPM mage makes you competent in all 5 categories, depending on how you spend your spells.

Now if you HAVE 5 players this is pretty easy; someone fills each role as a primary, another roll as a secondary, and can ignore the rest, perhaps one 'can do everything but with fatigue/location limitations' like a mage. However as the number of players decreases the requirement for each PC to reliably fill multiple roles increases.

My standard game is a grand total of 2 PCs and 1 GM (rotating GM with the PCs choosing a 'guest NPC' from the GM's list who they will generally direct in action). Thus it seems almost required that PCs be capable at ~4/5 above.

So thoughts:
What other sub roles do I need?

Have I missed any of the 'core' roles?

Why am I posting this:
I have been speaking a lot with co GM/player Kal about role playing in general and the rock-paper-scissors approach to PC opposition/challenges, and I am hoping to build, for myself and him, a better understanding of the ultimate 'distilled' abilities that makes up a PC.