totally just you. banner lords are certainly a decent faction, but far from overpowered. if i were to rank all the factions, they'd likely be in the upper half but certainly not the #1 spot. you just happen to have some of the best epic champions from the faction, which i expect is colouring your view somewhat. high elves are similar. you have the two top epics from that faction as well as two solid legos (and aleksandr). that doesnt mean the faction as a whole is overpowered, just that you've been lucky with your draws.

in regard to faction wars, that's honestly pretty normal. pretty much everyone starts out thinking that floor 21 will call for a team of 5 fully built 60s, but that's rarely the case. i think the only faction that took me a full team of rank 6 champions to clear was the skinwalkers and that's only because they suck (and shadowkin, but i already had 5 by the time the crypt opened).

Thanks!  Perspective helps.

Banner Lords was easy for me as well, but that's because Ursala trivializes that FW21 :)

Not quite the hard carry Scyl or Arbiter are for Barbs/HE, but built in Regen/Immo will just get you that 3*/consistent 21 clear quite easily.

Totally agree, Ursala carries that faction. I remember I had Archmage, Sethalia, Champfort alongside Ursala and my only DPS was 5* Gerhard the Stone. Slow af, but got the job done. 

I don't even have her built in anything fancy, DEF based RESIST/CRUEL/IMMORTAL.  Her Amulet is a 5* uncommon HP with crappy substats.  I can only imagine what she could do with a proper build.  You want to talk about slow, 8 minutes is my BEST time.