If it has to be TOS stuff why can't it be something interesting? A Arex novel? A M'Ress novel? Something continuing Christopher's post TMP storyline? Captain Spock before TWOK? Something with the crew of the Enterprise-A?
Not the 500th adventure of the five year mission.
Because Five Year Mission novels are the ones that sell the best. The marketing of supporting the type of novels that pull in the most money is pretty obvious, no?
Besides, I don't get all the complaints about "yet another 5YM book." In all honesty, I greatly enjoy them, and found with the ones released this year to be some of the finest Trek novels I've read in awhile. I agree it was probably a bit overkill for the first half of the year to pretty much be exclusively TOS, but I suspect that was partially due to STID's release and partially related to the plans for The Fall series in the second half. But it is a good idea, IMO to split the various releases up next year like they seem to be doing.