I see skellige - instant forfeit. It's just too boring.
I think this is a large part of the problem you encounter. People just cba to play a game they have no fun in. So they start a game, check who the opponent is, and they forfeit whenever it doesn't suit them.
I have this with NG, and since the last update with NR (I think NR is the OP faction at this moment, though not sure, just feels like that to me, and I encounter too many, gets boring, even if you can win). I don't think NG is too powerful, it's simply that they suck the fun out of the game for me, so no use playing them as often as you encounter them (I like the challenge now and then, and it's certainly possible to beat them, but like NR, it feels like majority play it).
Skellige I didn't find too annoying, but it's probably because it keeps changing, and the different strategies coming forth interest me so far. Also their "OP" deck/strategy often needed the last move to swing the battle in their favor and win (by a huge amount of points), but winning the first round, with only 1 card less, often solved that for me (a geralt at the end will decimate that score, or when playing skellige yourself, counter with morkvarg as the last card played). Of course you can't win them all, sometimes it fails, but well that's part of the game, I liked the challenge.
What annoys me now though is that after the nerf, I encounter them even more, though I see some different strategies from before, it's now just too often that I meet up with NR, SK & NG and MO, SY & SC seem to be lost even further in the avalanche.
I would honestly never forfeit agame against those factions, simply because you don't see them enough. But yeah, I defo forfeit matches that are basically Groundhog Day in this game. When they finally fix those issues, you probably fix the majority of forfeits (and 1 card passes).
What I also tend to do is just a quick play rather than forfeit. I am unsure it's any better for the opponent though, when I just smash all my 10 cards down in the first round just to get 1 crown (so I can complete my bonus crowns for the day). Today my NR opponent send the taunt "Are you a Jester?", and I seriously had to laugh, cause well, it must have kinda felt like it for him, but I was simply bored with playing another NR, and was just thinking I'd grab a quick crown, which would have no doubt ended in the exact same way if I played serious so yeah....
I think CDPR is trying really hard to balance things, as they should, but I think they are doing something wrong in more ways than one