Yet another GSSR suggestion request

Almost everyone says go caster if you don't have any of them. All the best supports offer different things, and having more of them offer more versatility and options with comps. Just remember that with gameplay here, good supports >>>>>>>>>>>>> everything else. That's why on almost every tier list you see servants like Waver at the top, and they practically never change their position while the rest of the meta shifts around them, because these lists are mostly written with the supports in mind.

Unless there's a particular five star you'd like to get, then I'd say there's no reason not to. Looks like you have at least a 4 star for every class (assuming you have Chloe).