I dunno about you guys, but I duel to improve my battle capabilities so I prefer to use my battle gear. I also like duelling as it is, don't really have problems with it. Being in heavy armor also has its disadvantages, wearing no armor has its advantages.
I like that I meet a variety of opponents with all types of weapons and armors in duels, makes for good and thorough practice. I also like duels with some armor cause there is atleast some room for mistake. Native duels are less fun because of the enormous amount of fluke based victories and defeats. After a cRPG duel I can be quite sure if my opponent or me is the better player. In native theres always one that makes one silly mistake while he can still be a very good player. Let alone the ridiculous OP'ness of the stab in Native. Native duelling is shit, does feel more responsive though.
Also, if you duel with no armor there is no incentive to use the slower but heavier hitting weapons cause 1 hit with 35 cut will do the trick too.
Why only a standard duel armor and not a standard duel weapon? Some weapons are way better. Some players use the Danish Greatsword while I use the Practice longsword, this made the results of the duel wrong.