(I put the spoiler warning in case somebody prefers to discover game mechanics on their own).
I've probably done around 125-150 Wrothgar dailies so far on my VR 16 characters, for the last 62 I wrote down what I received as a reward (whether it was a set item or not and if it was VR 15 or VR 16).
Based on that data I got the following values:
Wrothgar Daily Reward:
- Chance to get a set item (no matter if VR 15 or VR 16): 19/31 (61.29%)
- Chance the item is VR 16 if you get a set item: 4/19 (21.05%)
- Chance to get any VR 16 set item: 4/31 (12.90%)
- Chance to get a VR 16 set item of a specific set: 4/93 (4.30%)
- Chance to get a specific piece of a specific set that is VR 16
EITHER
4/837 (0.48%) for all pieces
OR
2/465 (0.43%) for armor pieces and necklace and 4/465 (0.86%) for rings
- Chance to get the best trait on a specific piece of a specific set that is VR 16
EITHER
1/837 (0.12%) for armor pieces and 1/628 (0.16%) for necklaces and rings
OR
1/930 (0.11%) for armor pieces, 1/697 (0.14%) for necklaces, and 1/349 (0.29%) for rings
Examples:
Chance to get VR 16 Briarheart Necklace with ANY trait (assuming the chance to get a necklace, in general, is 1/10 and not 1/9)
number of farming days: 30 60 90
with 2 dailies per day 22.79% 40.38% 53.97%
with 4 dailies per day 40.38% 64.46% 78.81%
with 7 dailies per day 59.55% 83.64% 93.38%
Chance to get VR 16 Briarheart Necklace with Robust trait (assuming the chance to get a necklace, in general, is 1/10 and not 1/9)
number of farming days: 30 60 90
with 2 dailies per day 8.25% 15.82% 22.76%
with 4 dailies per day 15.82% 29.13% 40.34%
with 7 dailies per day 26.01% 45.26% 59.50%
You can also find blue VR 16 items of the Trinimac's Valor, Briarheart, and Mark of the Pariah sets in treasure chests. However, for jewelry, that means that it won't be the best quality available ('cause the item is only blue and the quality of jewelry can't be updated with crafting).
Also, VR 16 set items in treasure chests are quite rare, even for characters that have the Treasure Hunter passive ability from the Champion System. And even in Hidden Treasure chests obtained from Orisinium Treasure Maps, the chance to get a blue VR 16 set item is quite low (about 1/4 I'd say based on my experience).
I've decided to post this data here, since it might be helpful to know for some players.