It's certainly not my intention to stir up any alarm with posting on this, but the fact is Rockman DASH 3 has been dropped from Capcom of Japan's front page. I wouldn't necessarily even worry myself about something like this, save for a few months back the same thing occurred with Mega Man Universe. A week later, it became apparent why that happened. Of course there's a huge difference between Mega Man Legends 3 and Mega Man Universe. Universe underwent months of quietness, whereas Legends 3 still has updates and progress reports ongoing; albeit it is true that things have simmered down since the Prototype Version was announced to be delayed. Furthermore, combining this with the uncertainty surrounding Mega Man Legends 3 being greenlit does add cause for a lot of concern.
As it stands, Rockman DASH 3 is still listed on Capcom of Japan's full game lineup. Then again, Mega Man Universe is still there too. Still, my sensible side says there's no way Capcom would drop a game so passionately desired by fans, not to mention one that fans are contributing actual content to. People have made a lot of personal investment in this title. And of course there is no announcement of cancellation on the game's homepage nor the Devroom.
So long as the site and Devroom are still running, I don't think there's anything to fear. Hopefully we get some kind of good word soon; I don't like having all this worry!