Before anyone gets too excited, You've Got a Habit of Leaving isn't a new number per se. In fact it's one of the first songs ever recorded by Bowie, dating back to the early sixties. The original version was released as a single in 1965 and its sound and structure is highly indebted to The Who.
This "new" version was recorded about twenty years ago for the Toy album that was shelved by Virgin and remained unreleased until 2011 when David Bowie released it online. Before that, the track surfaced as a B-side for the singles culled off the Heathen album. While it's certainly not worse than some of the songs off of that album, it's not in the same league as some of its best tracks like Everyone Says 'Hi' or Slow Burn.
So this isn't David Bowie's next phase. His career coda was the hauntingly beautiful Blackstar. This is merely a souvenir, a postcard from the past. While it's a treat to hear the man's voice and to discover (or re-discover) a forgotten artefact from his prodigious output, it shouldn't be considered with the same reverence as his other, more complete artistic statements. I don't expect this to be a song that die-hard or casual fans will revisit often.
Still, it's Bowie and unlike Prince, there probably aren't thousands of recordings in a vault somewhere. In the morbid business of nostalgia for dead artists, this is probably as good as we can expect from the estate of the Starman.