No you

Rare = Middle Ground

Once you play long enough, you will have at least one rare of every faction. So the requirement seems ok to me.

if you do not have at least ONE RARE for a Faction you do not really have any Business in that Faction Dungeon ...........

There is no real reason Why anyone would build a team of UNcommon or Common as a Faction team ...........  

WAIT I AM WRONG , I built a  Demon Spawn Team with Demon Spawn , Vile Spawn , and Pit Cur

Put 5 star Common gear on them and lvled them up to 40 because they were FOOD ANYWAY

then I popped them up to 5 star and feed them to my Valkarie 

NO I didnt book them , or Glyph the armor either

So you can Beat  a Faction with Uncommons , you just not going high

as for a RARE,, you got one as your starter,,, 

and you got another one when you did the Noobie Missions the first couple days

and Seriously, if you are Doing Missions and Quests you get  Ancient shards ... More rares

and the First MONTH you get 3 Ancients,, 2 Voids ,, then a EPIC Kartum all Free

So,, You get some rares ,,,,,,,,,,,,,,,,,,, Play the game like the rest of us FREE TO PLAYERS ,,,,,,,,,,,,,,

OR , Buy Some Gem packs and have At it 

You can farm rare champions of the following factions in campagne:

Bannerlords (Act 1), Lizradmen (Act 2), Undead (Act 3), Dark Elves and Skinwalkers (Act 4, you can get Spirithost here), Ogryn (Act 5), High Elves (Act 6), Orcs (Act 7), Sacred Order (Act 8), Barbarians (Act 9, you can get Warmaiden here, a really usefull champ), Lizardmen (Act 10), Knight Revenant (Act 11), Demons (Act 12).

The only factions that have no farmable rares are Dwarves and the new faction, while the latter has not even a crypt yet.

LOL...you guys are looking at it opposite from what I am.

I usually carry only Legendary/Epic - I fodder just about all my Rares except the ones I've started with (Kael, Apoth, Athel, or Executionar) but i'm not going to carry a Rare per faction when I don't need to.

Faction wars is just farming for me - I've already completed it all.  (been playing for a long time).  It's a simple annoyance that can go away.