I think it's a balancing act between transparency and giving too much information away. I work for one of the world's top three software companies, and we give customers an idea of what is coming in the future, without over-promising or disclosing too much. It helps with planning. And there are select audiences that we brief under NDA a year-plus in advance about very specific plans. It helps customers and these audiences know that development is active, there is a roadmap, and that their continued investments are a good thing. Also provides customers and other key audiences an opportunity to provide their feedback and input early enough in the process that it can improve things and make a difference. Not saying feedback always drives changes, but it's helpful to get it early and to hear the customer's perspective.
On the other hand, as the owner of a small niche forum, I don't need to know XF's product and feature roadmap six months or a year in advance. But it would be nice to have some idea what's coming down the pike, even if it is just a few months out from release.
One area I think XF has done a great job is informing customers well ahead of time that various versions will be / have reached EOL, and that technical requirements are getting upped.