I played For Honor for the first time at PAX West a couple weeks ago, first in the more standard 4v4 control point mode and then its 1v1 duel mode ahead of the closed alpha this weekend. You can watch the uncommentated video above to see how well I fared in my fights (spoiler: pretty well.)
While I enjoyed For Honor quite a bit—and damn is that game pretty to look at—I'm not sure if its combat system is deep enough to support a duel mode on its own. It works fine, but isn't deep enough to hold my attention for very long. While playing through the tutorial, I couldn't shake the feeling that someone at Ubisoft played Chivalry: Medieval Warfare and then went to the head of a long table in an ominous meeting room and said "how can we make this but easier?"
Combat mostly consists of swapping between three weapon stances; left, right, and up. If you are attacked while in the same stance as your opponent, you will automatically block that attack, so For Honor becomes a simplified game of 'Rock, Paper, Scissors'. You can easily see which stance your opponent is in before and while they are attacking, so you want to quickly switch and match them to defend, then try to swap to something else and attack to catch them off guard.
There are special attacks and guard breaks as well, but this stance swapping is the crux of it all. In the 4v4 mode I played, each character also had special abilities that they would unlock as they level up, but those aren't available to use in 1v1. Those abilities and the chaos of team fights kept the control point mode fun, but the duels felt sterile without the added layers on top of regular stance combat. Not lacking skill and finesse entirely, mind you, just with mechanics significantly more transparent than that of Chivalry, where 1v1 duels are more of a complex dance than a hack 'n slash matching game.