OK, you're a 'lookout'. That's great in a situation where someone needs to be doing that job.
Ahh, but you see, that's my point.
If you're the kind of player who wans to have different, distinct roles- not my style, but ok- then adding roles helps wiht that. Everyone still gets equal time in combat.
OTOH, my preferred method would be universal noncombat roles.
There are 1000's of different situations that you're all lumping into 'non-combat'. Non-combat DOESN'T EXIST. It is a negatively defined open-ended category. For instance, what do 'lookouts' have in common? High Perception?
It depends on the system, but you could easily defined universal roles for a broad variety of noncombat roles, but focusing on mechanics.
An example. A lookout is a support role who's job is to oversee the caper and make sure that everything is going to plan, and that no unexpected events derail the plan. They serve this role no matter what the caper is-
*In a stealth mission, they're the one keeping an eye on the guards or the people looking for you
*In a social mission, they're the ones making sure that you get some time alone with the target
*When gathering information, they know the best places to ask, and who to keep out of earshot.
*In a travel mission, they're the navigator, keeping an eye out ahead of obstacles and changes in the weather
*While doing research, they're the one who finds the tomes and maps, while some others pre over them or make notes.
*While sailing on a ship, they're up in the crows nest saying 'land ho!'
Each of these actions are more or less the same- they're an information role. In such a system, the gm might arrange
complications that get in the way of the goal, and
nodes which you can exploit if you know they're there. Seeing those complications and nodes coming is a good, story-resonant tactical role for a pc to serve in.
Some other roles for such a system might be:
Interference: A noncombat tank who takes on complications head on. In a social task, they're distracting the grand vizier while their allies speak to the princess. In a wilderness trek, they're carrying a heavier pack, or hauling people up a rope. Using the language above, interference roles work to negate complications.
Fixer: A controller/leader who changes the state of play. In an underworld information gathering trip, they're calling in favours, and running down snitches. In a stealth mission, they're providing disguises, or blowing out torches. Using the language above, fixers work to exploit nodes.
Face: The up front guy who gets the deal done. A face focus's on results, a striker-type depleting the 'hit points' of the challlenge faster than the other roles. When researching, they're doing the heavy reading, even if they don't want to. When bypassing a trapped room, they're the guy with the lockpicks standing on their head.