I've always been an advocate of the abstract idea that the Myst series and Uru, though they share a universe, are totally separate. I don't try to connect them temporally, I just enjoy them as separate and unique stories.
Theoretically though, it has been a few years since the DRC left, and K'Veer at least looks just as we left it in POTS. The shaft is prett similar too. I've jumped off of it before in POTS, and the bottom looks very VERY much like what we see in Myst V. So it's entirely possible that, from the new DRC storyline standpoint, Myst V has already happened.
Though we'll never know until someone at Cyan gives us an answer