The title says it all: the suggestion is to make the repair of base structures give credit towards objective support ribbons. The reason for this is that it happens way to often that players move on from a captured base without caring to restore the base structures including generators, SCUs or turrets. Awarding ribbons for this seems like a reasonable incentive.
There is already Ribbons for repairing in general, I am not sure a specific base repair ribbon would help that much.
Well, one would gather progress towards repair ribbons and objective support ribbons, both of which already exist. The thing is that many players are too tempted to move to the next base, because there is more XP to be gained by killing a straggler or repairing vehicles on the way, rather than securing the base. A few players deciding to stick around longer would benefit the gameplay, especially if the fight comes back to the newly captured base.