The scouting role isn't one I had considered, because any Raven Guard can probably do it better- but you may not have a Raven Guard or that supplement (they get a cheap talent that removes stealth penalties from wearing PA)
Then again, any DW Marine could simply opt for wearing Scout Armour instead of PA.
But of course that'd make him a little more squishy, and if the established group dynamic works, there's no reason to push the character out of one of the few areas where he's actually useful.
combat drugs, gratuitous cyber-enhancement
Depending on the specific item in question, those might enable him to "transcend" his supporting role, though. If the player is satisfied with being the group's pathfinder, or "automap", to use your example, and everyone in the group agrees that he should not get too close to the combat efficiency of the Marines, then any such enhancements should be limited to enhancing noncom tasks.
From the drugs you mentioned, the Pain Suppressant might be useful to keep him alive. Frenzon on the other hand just sounds like a ticket into an early grave, considering that the enemies in DW are scaled for close combat with power-armoured, unnaturally tough Astartes. Unless you include special opponents just for his character, but this might be tricky as they could get easily taken out by one of the Marines.
