Sanzaru's a good developer, they did a great job with Sly 4. I thought Shattered Crystal was terrible but it was pretty clear that it was also rushed together and made with not enough time spent at the design table, so I could see Sanzaru doing better with this second shot.
Also, no new trailers and gameplay demos could mean that Sanzaru is spending more time actually developing the game. Stuff like that can eat into development time as well.