I think the reason why they decided to make ssj4 gogeta a defense type it is because he barely does anything in the anime and aswell holding back his full power the entire macth with omega shenron.
All fun and games until Gogeta SSJ4 drops from 50% to 25% of his hp just from a blast and a strike from Vegito blue LL and you realize this guy is still the anniversary star a year after his