Are there any technical reasons for putting features like paginated reports and Calculated Groups in Premium?
If not, I think that is a mistake. PBI adoption is a bottom-up process, and it is a big step to go Pemium or for an ISV, to Embedded. Let enthusiasts evangelize with all the features available, then make the decisions about investments.
The whole point (one of them at least) with cloud computing is that everyone can have access to the same technology, just with different numbers of users.