AoE2HD is NOT developed by the original Ensemble Studios staff.
Instead, devs of the Forgotten mod were hired to work on the Forgotten Empires expansion, while trying to maintain basically a fork. The HD edition has been a lackluster, though, with new bugs, multiplayer lag/sync problems etc.
I'm still entirely convinced, that the original AoE2 (that you can buy in a box on Amazon) with community patches and Voobly multiplayer client is a much better game to this day. I've bought the HD only for new campaigns.