Based on the excess starting loot, it kind of feels moot to try and check for morale boost when it's so easy to build an army past level 12... one has to dig really far to see if your level 15 army is affected by morale boost. Camps and Outposts normally don't spawn higher than your own levels.
Perhaps a new reset is required, where everyone is given standard base loot or slightly more. The units that we can research also affect the outcome of forgotten base raids, where said issues moral boost solves begin with something like a level 19 base being attacked with level 12 army with level 11 units.
To see how moral boost would affect players digging when they have a limited army diversity, we should probably lower the Tiberium, Crystal, Credits, Research Points and perhaps power to a standard vanilla world. Maybe applying a repair time discount in sync with the moral boost would allow players outside the PTE to attack high level targets.