There's been a large number of complaints about the small drop of weapon and jewerly for the new sets introduced on One Tamriel. I have a fairly simple solution. Just like Orsinium, add daily missions for Delves and World Bosses in every original zone in the game and make it so that it has a 100% chance of dropping a weapon or jewerly from one of the 3 sets in the zone. Also make them have a very small chance to drop one of the original motifs (9 races, Ancient Elves, Barbaric, Daedric, Primal and Imperial). So, to sum it all up:

1- Add daily missions for delves and world bosses in every original zone;
2- 100% chance to drop one weapon or jewerly from one of the 3 sets in the region;
3- Small chance to drop one of the original motifs (9 races, Ancient Elves, Barbaric, Daedric, Primal and Imperial);
4- Make sure to change dailies from Orisinum, Hew's Bane and Gold Coast to use rule 2.