As part of the Q&A on YouTube last night it was mentioned that Base personnel may be coming into the game at a later point in time.
I'd like to suggest a different way of approaching this: How about instead of having dedicated base personnel which amount to nothing more than a number on a spreadsheet, instead the bonuses that could be provided by base personnel are provided via PP soldiers in the form of perks?
The perk system already exists in game, however at the moment it only aids in battlefield operations, it wouldn't be a difficult task to include new perks that might give a bonus to say production, research, building new facilities when a given solider is present at a base.
Doing this would give some interesting choices to players both when recruiting ''Do I recruit the guy who has a return fire perk, or the guy who can make production of XYZ 10% quicker?'' and when selecting perks for level up ''Do I give this guy a return fire perk, or do I give him the production boost first?''
Those solider could have the possibility to be taken on missions, (maybe even linking to mission objectives - ''this mission needs someone who will be able to perform research in the field) and in particular those scientist/engineer soldiers would be able to be actively involved in defending bases that come under attack.