First, in order for this idea to work, the number of squad slots must be increased from 5 to 10 using all of the number keys.(0-9) This will also require the squad area of the commander HUD to be expanded to fit the extra slots.
Here's the idea
When a commander builds a certain structure, that structure is auto-added to a squad. It's icon will appear in the squad area on the commander screen when the structure is built.
The structures that will be auto-added are as follows:
Armory
Arms Lab
Observatory
Prototype Lab
(only these structures are auto-added)
The commander can still add player squads to the squad area by selecting players and pressing ctrl + slot#. (0-9)
If a Commander builds multiple observatories or armorys they will also be auto added.
This means that with the 10 slots, there is room for:
2 armorys
2 arms labs
2 observatories
1 prototype lab
3 marine squads
If a commander wants to override one of the structures that is auto-added he can do so by adding something else to that slot.
It is unlikely in a normal game that you would need more than 10 slots for players and structures.
Most experienced commanders probably already add structures to the squad slots. Especially Observatories. Auto adding them will teach new commanders how to use squads and remind them to upgrade since the icons will always be there.
Some other possible options would be to gray out the icons when that structure is in the upgrade process so you know exactly when the upgrade is done or make the icons turn red when that structure is under attack. Displaying health would be nice too, but I don't know if thats possible.
Auto-adding structures does not change gameplay, it just allows the commander to focus his attention on his marines.
He can upgrade armor, weapons, scan, etc. without ever looking at marine start or clicking on any structures. With extra slots, there will be plenty of room for both structure and player squads.
What do you think?