Total cost: 1,000,000
Cost per member: 33,333 gold, going to round this up to 35,000 just for simplicity.
Next is to figure out the "cost" of each table. There are a couple ways to do this.
Gem ratio is 5:7:12 which would make the values 7.3k, 10.2k, 17.5k
Glory ratio is 1:3:5 which would make the values 3.9k, 11.7k, 19.4k
Arcane ratio is 1:2:3 which would make the values 5.8k, 11.7k, 17.5k
Averaging those out and rounding we get:
Table 1 = 6k
Table 2 = 11k
Table 3 = 18k
For each item on the tables ask yourself if you'd pay that much gold for the rewards. Would I pay 6k gold for 20 minors? Certainly! Would I pay 11k gold for 30 minors? Yup. Would I pay 18k gold for a random legendary? Probably not since chances are it would just be disenchanted into 100 souls.
If the legendary was changed to 2 random legendary it would closer. 3 random would be a really nice reward and even if they were all duplicates it would be "on par" with table 1
Edit: I should add that I don't think the rewards, in general, are too low. I think they serve as a "I have too much gold and nothing to do!" outlet while keeping the gains on par. The lower rewards are roughly equal to gold keys with a chance at getting gems and whatnot which are more versatile. Just want to make sure the rewards are balanced against each other.