>>36307411The games are already trivialized so it's not like the double battle thing is any worse
So really if they had devs who knew how to balance at all for the single player making tweaks for multi would be no problem. Start with battles that are easy, eventually game ramps up to make it so you're going to need to use teamwork, for example enemy teams type cover themselves, use disruptive strategies, etc. Colosseum and XD were fairly good at this and you see it all the time in battle facilities, just make that co-op and you're good.
But cooperative turn based games or strategy games are usually a pretty bad idea anyway, so it'd probably be better to make the cooperative elements just in the overworld, or against wild Pokemon.