The first one means they just need to see more about what people really want with the mystic, and are possibly going to do a major rewrite. The second one means they're confident with the class they've built, but want more options and are opening it up to fans rather than doing it themselves. Either one likely means that the playtest results were conflicted.
I'm not sure how I feel about either interpretation. Fans can make some good stuff. After all, we often like our own work better than the official rules. On the other hand, it just seems so driftless letting it float around like that and seeing what comes back. I also feel like I have no idea what to expect with a follow-up playtest now.
Well, I'm glad they had the guts to pull it instead of putting something out just because it was expected of them.
I was so sick of the vast, poorly-tested output of 3.5. Good they're being really careful not to make those same mistakes, even if they risk some annoyance in the process.
The best design comes from throwing lots of stuff out and only releasing it when you're proud.