Regarding the vagueness of their demands: they're good enough for a start. A good internal organizing strategy is to collectively write demands so there's utility in having something to start with and build on.
Actual achievement of demands in a contract requires negotiation. If the union achieves recognition from Amazon (unlikely) or from the NLRB (a long process) then the Amazon will be legally required to negotiate (though not to give in.) Pressure will be required upon Amazon for any real gains.
But even without recognition, this is a threat to Amazon management that must be listened to. Many workers find that even the threat of a union drive can achieve results in changes by management even if the drive isn't successful.
All tech and warehouse workers should support this, because an upward change in conditions at Amazon will put positive pressure on the labor market.

Go union!

Articles like this should compare apples to apples. How does Amazon warehouse wark compare to other warehouse work? Amazon gives stock options, do other warehouse workers? Amazon will pay up to 95% of your education, do other warehouse jobs?

They should have a right to take it to a vote, but be wary. Amazon is famous for negotiating deals. If they unionize the union will now get some of the money and I am sure Amazon isn't sharing their slice of the pie. The union also can't negotiate things like the stock options and paying for workers continued education. So if workers cast more what is the first thing to go?