It would be useful if specialists could gain experience by completing missions successfully and that experience could translate into improving their performance. The improvement performances do not need to be huge, just significant enough. It seems daft that a player can reach higher levels but still have to wait ages for specialists to perform their functions unless the player is willing to spend real money. Real game advantage should be a reward for experience within the game not based on size of pocket book!

eg
1) General:
Gain 'General' points for each camp cleared or number of units destroyed (and loses 'General' points for own units or battles lost?)
'General' points could then translate to items such as map movement speed, interzone movement speed and/or number of units which could be assigned.
2) Explorer:
Gain 'Explorer' point for adventure searches scaled to whatever they find and translating to speed and/ or cost of search improvements
3) Geologist:
Gain 'Geologist' points for each resource located scaled to which resource they are hunting and translating to speed of search improvements