Before a Poland community manager said that part of the function will be provided free for pre-expansion players. Now the information got Community Manager Grimiku confirmation from American War Forums.
We want to implement a lot of the new systems and features in a pre-expansion patch for free. That should include Paragon 2.0, Loot 2.0, Loot Runs, and Nephalem Trials. For now, you'll need to purchase the expansion to play as the Crusader, explore Act V, unlock the Mystic, and level up to 70. These details may change as development moves along, but we want some of the core gameplay improvements to be available for everyone.
The new Paragon system will remove the Paragon level cap (meaning you'll be able to, well, infinitely level your toon), which is good news for the few and proud that have reached the max paragon level. There'll also be other changes Paragon 2.0 will bring, and we'll get those then too.
The Loot 2.0 vision for Diablo 3 will be especially important for those that want to get characters ready for the expansion. Loot 2.0 means that the gear drops you get will be more focused on your current character, which means that in general, gearing up should be easier; and that there should be more 'reward' for playing the game.
The other features Grimuku talks about, the Loot Runs and the Nephalem Trials, are end-game modes/activities. Blizzard seems to be taking a new direction with Diablo 3, addressing some of the fan complaints.