How was it "highly" inflexible.
The only seriously restrictive thing was the 24 hr check-in. I mean, you either have some form of internet access, or you don't.
Flexible:
1) Share your library with up to 10 people. I can share a game with however many people are in my house right now and that is it. Xbone would have let me share with my brother in a different city, my cousins and nephews in another state, and friends in another country. Xbone wins the sharing fight.
2) By and sell used games. We did not see a list, but I would bet that 'approved retailers' would have included Gamestop, Target, Walmart, and Best Buy, at the very least. Maybe a few more regional brands like FYE and some others. Ok, so I could not garage sell, or flea market these games. On the upside, the publishers would have good hard numbers to gage the used game market (as well as share in the profit of that market). Upside being the very real possibility that price could come down for games based on real market numbers. While first glance makes this a restriction, careful thought shows that the Xbone wins the used game fight if by no other means than getting the publishers on board the used games ship.
3) Digital downloads. Transferable liscenes, like those needed to buy and sell used (disc based) games could be extended to digital games. Also, digital games could be gifted from your library to another gamer (as long as they had been on your friends list for at least 30 days) one time per copy.
I could go on, but the point is, this was true innovation from the leader in the industry. Too bad the luddites of the internet (Gawker, IGN, et. al.) are too scared of the future.