Agreed mostly, in some ways it is a demo though, anyone who wasn't lucky enough to attend an event and get a chance to play, this is they're first hands on experience with the changes made, so in that regard I can understand them wanting more such as a lost sector to play through. I also believe on Bungie's part along the design path should have had this in consideration, the beta is extremely limited in a sense like it was a last minute toss together. Using D1 as a reference it was what 3 months till the first DLC, to me that's not terrible, but since Rise of Iron there has been no significant content, people are itching to see something new.