Following my previous post for why I think they should stick to the original 6 teams + Angmar, if they
were trying to make more factions to represent
all groups of Middle Earth, then this would be my recommendation, influenced by my favorite board game: War of the Ring - 2nd Edition.
Free Peoples: Gondor, Rohan, Elves, Dwarves, Northmen (Hobbits are with Northmen because they protected the Hobbits)
Shadow: Sauron, Isengard, Southron/Easterlings (Those are the factions from WotR, but to balance Reforged, I'd adjust Shadow to be: Sauron, Isengard, Southron/Easterlings, Angmar, Goblins)
Not going to lie, their plan to do 6 + Angmar resulting with 7 factions bothers my OCD... Needs to be an even number
