Honestly, so far the UA has existed in a weird in-between space for me. It's way more than just consolidating the Everything class/race errata into a convenient book for new players to start from, but far less than a full scale revision of the game. The only playtest packet that really wowed me was the first one, as I thought the new backgrounds & species are a way better way to create a character than the 2014 rules. Since then, it's been hit and miss, but mostly just different. Maybe once all the classes are revealed, it will start to make sense what they are trying to accomplish. My guess is that they're trying to make starting the game at level 1 much easier, while giving it more depth past level 3.
What I worry about is that they are overfocused on 'fixing' balance issues that only exist on a white board, or trying to raise the overall popularity of classes that are adored by the people who actually play them (druid).