So did a small batch test of Vitality today...and the results are meh.
Took a Rank 50 Gladiator against a rank 50 Amalj Drubber (Monk Class Mob)
Vitality Stats
VIT 311
DEF 643
Took 124 attacks from the drubber for a total of 13,575 damage
81 non weaponskill attacks for 8,637 = AVG 106.62 damage per hit
43 weaponskill attacks for 4,938 = AVG 114.83 damage per hit
124 total attacks 13,575 = AVG 109.47 damage per hit
Non Vitality Stats
VIT 250
DEF 631
Took 124 attacks from the drubber for a total of 14,461 damage
81 non weaponskill attacks for 9,112 = AVG 112.49 damage per hit
43 weaponskill attacks for 5,349 = AVG 124.39 damage per hit
124 total attacks 14,461 = AVG 116.62 damage per hit
The VIT difference between the two was 61 VIT.
The Damage difference between the two is 886 Damage.
Will have to do long term tests to verify the small batch data results. Keep in mind this was against a mob that was able to land "Defense Down" so that does somewhat skew the data. If anyone is interested I can post the lows and highs as well