I not gonna lie, I don't have a vast pool of experience from which to draw from in this particular matter (new tau codex rumors being reasonable or not), but in my humble opinion it is best to just ignore the majority of rumors.
It would appear that Games Workshop's schedule for release is a new codex every 3 months (those months being January, April, July, and October). Now, maybe that is just a fluke, or maybe it could even speed up, or maybe I am COMPLETELY mistaken and someone will be polite enough to correct me shortly after I post this
... but I think it has happened enough times in the recent past to be a reasonable assumption for the future. That having be said (or more appropriately, THEORIZED
), there are still two codices for 2010 that have yet to be named.
This could potentially see two non-Imperial armies released... possibly one from the group of Dark Eldar/Necrons and one from the group of Eldar/Tau (this is not even speculation as much as a total shot in the dark
). Alternatively this could potentially see two MORE imperial codices (Inquisition and Redux Dark Angels for instance). Even more alternatively, we could see a non-imperial codex in July, followed by an Imperial codex in October... thus evening out the tally for the year to Two Imperial and Two non-imperial.
I have presented this "theory" in opposition to rumors because I don't feel that there are a lot of rumors that really hold a lot of merit. I don't recall having heard a lot of rumors about space wolves getting a new codex before they came out, or for Tyranids either. Now, maybe I just wasn't looking for those rumors, because I was too busy looking for rumors about the tau... but the impression that I got was that there is a rumor for every possible outcome. When there are so many rumors that all bases have been covered, you no longer have a list of "things that I heard might happen"... you have a list of "things that could statistically happen".
So I guess it's not that I have a problem with rumors in general, or even the specific rumors that are floating around at this exact moment... it's that there are five hundred different rumors, that are all equally confident of their righteousness.