Everything about Diablo 3: Reaper of Souls leaves me wanting to more, despite the fact that I've already cleared the campaign on multiple occasions, and I wouldn't be shocked if I've got a full roster of level 70 characters by the time the year comes to a close. It's been a long time since I enjoyed a hack-and-slash title as much as I'm enjoying Diablo 3: Reaper of Souls, and I plan to milk that for all it's worth. I suggest you do the same.
If you've already played the game on the Nintendo 3DS, it's unlikely that you'll find anything in the game's PC port that would justify a second purchase of the game. Unless you're feeling particularly supportive of Image & Form, and/or you despised a particularly aspect of the game's user interface on the 3DS, save your cash and play your existing copy of SteamWorld Dig.
I see little reason why longtime fans of the franchise would be disappointed with Black Ops 3. It may not draw in many new fans, or convert those who've never been big Call of Duty fans. But there's more than enough here to keep the game's existing community locked in digital combat for another twelve months.