Add the possibility to order new and/or assign excavators currently in the construction queue to mining towers.
When I realize I need to add excavator capacity, currently I have to:
1. note which tower needs more capacity
2. locate the vehicle depot, order the excavator
3. wait for excavator to finish, then assign the excavator to said mining tower
This could be very simplified if it was possible to order a new excavator from the mining tower dialog box, which would then be preliminarily assigned to the mining tower. (Or, at least, let me assign excavators to the mining tower which are already in the construction queue.)
