The ending doesn't make sense? Spoilers Farseer & Tawny Man

['thul]

These beings have a strong feeling that despite it being theoretically possible, Fitz will not feature in further books as more than a small side-role.
If RH keeps with the style (and does not finish up the story of the realm of the Elderlings in BoD), then 'thul think that further books would be placed a few years (maybe 5-6, maybe some more) after the RWC books. If that pattern holds, then Fitz will simply be too old to be main character. He can still be a wise old skillmaster, but his life is too happy to easily tear up for another adventure.
On the other hand, add the years between tawny man, rain wild chronicles and these potential 5-6+ years after that again, and what do you have? You have just enough time for the heir of the six duchies (and out islands and mountain kingdom) to be old enough to get into trouble on his own... and if he's got siblings, drag them into trouble.