I'm going to remain cautiously optimistic about this one. I'm a big fan of Cowboy Bebop, Samurai Champloo, and for the most part Space Dandy also. Kids of the Slope ranged from just OK to pretty good, but the end left me a bit underwhelmed, and I haven't checked out Shinichiro Watanabe's other works. Lazarus sounds like it could be promising, though the animation in this preview trailer seems to be a little rough at times, I just hope the storytelling can rise up and approach the level of Bebop or Champloo!
Your caution is warranted. I like most of his works, but I do think his story telling might not be his strongest suit. Don't get me wrong it's great but I think where he excels most is in combining music and animation like no other.
I hope so. I liked Carole & Tuesday. And I understand not everyone will find its story engaging. It has a lot of fill-in-the-blanks for it to provide the full narrative experience.