Pirates was a great game for so many reasons. 3D can only serve to draw attention away from those things. It's a game that doesn't need to be cloaked in the latest technology, and that will only serve to mask what made the game great in the first place.
Imagine a classic Stones album...say "Sticky Fingers", and Warner decides to re-issue it with digital mastering, new echo/reverb, heavier compression and limiting like the modern alt/rock bands use...it would be a complete disaster.
I don't think producers are looking into what games would be best served by 3D technology, but whether a game had a big enough fanbase to come back for the new version. And what could be more uninspired than that?