Project's also must have obligations to investors and don't promise impossible tasks, one good idea is not enough, for success need properly planned roadmap and honest team.
Yeah, make the project always on the roadmap path and the schedule does not change from beginning to end, it's like one way to respect investors. The rest, let the investor assess whether the project able to attracted him or not.
I do think they should give updates in accordance with their roadmap and if there is any delays, they should inform the community as well.