Wow, bittersweet news.
On the one hand, IG made one of my all-time favorite games, "System Shock 2". And I really like "Bioshock" - well, most of it. The last third goes downhill fast but I can definitely forgive that.
I'm not sure I can forgive the huge squandering of talent that "Bioshock Infinite" represented to me though. It had a great story, but one in which you have very little participation as a player and never feel that you're "driving" events. It created a great world, but you couldn't actually DO anything there, except for some shooting mechanics that had no bearing on the story and never really worked together. Creatively speaking "Infinite" was Levine's worst game, at least of those that I've played. Just walking along a linear path shooting various unnecessary distractions is absolutely not what I want from the guy who created "System Shock" and "System Shock 2".
I'm still surprised - commercially and technically, if not artistically, "Bioshock Infinite" was a huge success. But then, to me, it was such a huge step in the wrong direction for Levine that I'm kinda glad that he's gone on to smaller projects. I hope that he rediscovers the magic that made "System Shock" the most compelling game that I've ever played, and channels some of that magic into a new project.