I think a no-show at e3 might be cause for some concern, unless they address it in this month's update. At best, it would mean a delay is likely - at worst, they could be struggling to get things to where they need to be. It isn't easy making a masterpiece and my worry is that Shenmue 3 will not hold a candle to its predecessors. There's still a lot of work they need to do in regards to the Kickstarter rewards as well.
However, a no-show would totally be mitigated by a Shenmue I and II HD reveal. It seems imminent, the time is right, and it's the only course of action since the very beginning that makes sense. I know I can dig out my Dreamcast at any time, but the idea of playing a polished re-release on my PS4 (which I bought primarily for Shenmue 3) is exciting, and would really hype me up for the sequel. Really hoping for some footage in the May or June update (or, obviously, an e3 showing) to reassure the fans all is going well.
On a side note, I had a weird dream the other night that Shenmue 3, due to development woes, ended up being a stripped-down, first person point-and-click adventure game released just to tell the story. Eek