Seems I am very often having to clear a formation to make space for a new formation, only having to remake that same formation later on. Would be great if we could have up to 10 formations that can be saved. If I am not wrong, formation data could be saved on the phone as IDs that point to heroes in the player's data. It shouldn't have to require extra database commitment.
But anyway right now I have a team for gold mines that is shared with tower of despair, a team for capitol, a team for raiding, SDD team for events, the arena team, and now for this event a 4* only team. There was also an experimental tank only arena team I had to erase forever.
Would be a nice quality of life change to add more formation slots, but I guess not super urgent.