Doesn’t even need to be new classes strictly speaking. More outfit options, more hairstyles, facial hair options and maybe face paint would go a long way.
More weapons and weapon mods would be fantastic. Such as the rifles with under barrel attachments, it would be cool if you could switch what that under barrel attachment is so it’s not just the grenade launcher. Maybe a masterkey shotgun, or a special flashlight that messes with Pred camo.
More melee weapons beyond daggers would be cool too: swords, axes, machetes…
I love new Preds as much as the next guy, but I mostly play Fireteam, and it would be fantastic if there were more options to customize/personalize your soldiers.