There are lots of ways Adobe could have made this more attractive to consumers.
Instead of a one-year rental, they could have offered longer terms at discount. $20/month is actually not a bad deal. But that's their "special introductory" pricing for CS6 owners. That creates uncertainty and Adobe has pretty much said they intend to jack up the price next year. If I could lock in for $20/month over 3-5 years it would be much easier to swallow.
No reason they had to base it on unlimited usage. Allow persons who don't use every program every day to pay a small fee when they are using a program.
No reason why the model had to be based on unlimited programs. They could offer a plan where people would pay for their choice of 3, 5, or 8 programs for example. You want Photoshop, Illustrator and Dreamweaver. Somebody else needs Fireworks, InDesign and Dreamweaver, etc.
Point is, Adobe adopted a very narrow profit-maximizing model, rather than a customer-based model. Scott Kelby and others who owe their living to Adobe can talk to their blue in the face about what a great deal this is, but the customers know otherwise.
If you offer a choice and people take you up on it, it's a good deal.
If you don't offer a choice and force people to take something, it's not going to be a good deal.
Adobe, sadly, didn't have enough confidence in their own product to try to win customers by attracting them to the product, instead they chose a forced model.