An official reply from the Community Manager in the Blizzard forums revealed interesting new info about the Diablo III: Reaper of Souls — Ultimate Evil Edition:
We’re still working out all the details regarding if and how Ultimate Evil Edition will be supported post-launch (e.g. will we patch the game after it ships? if yes, should we only patch to fix bugs and address critical game issues, or should we patch in new content as well? at what frequency should we patch?), so we don’t have an answer for you right now. That said, I can confirm that UEE will ship on all platforms with all updates included up to patch 2.0.5, and that there will likely be a “Day 1” patch to add in patch 2.0.6 content, too.
As we move closer to ship and finalize our post-launch patching plans, we’ll be sure to keep you updated. Great question, though!
In other words, while the game will definitely receive any necessary and critical updates, the team is unsure at this time whether they will be releasing any additional content in future patches. Meanwhile, the Ultimate Evil Edition has been confirmed to include up to Patch 2.0.5, mostly likely along with a Day One 2.0.6 patch.