I agree that morale is largely cosmetic and you get pretty much the same results with Good as with Superb. However, the main problem for me is that boosters are only a temporary fix. After you apply a booster the morale will return to its previous state after the match (with some movement possible depending on the result of the match played). So if you rely on boosters you're just going to get in to an ongoing loop of applying them before every game... which is obviously what Nordeus would like you to do. The alternative is just to accept lower morale for a few matches and allow it to come back up naturally with results.

I've had seasons where my teams morale has stayed around Superb and seasons where it won't go above Good. Never seems to affect the results.