Idly wondering here. Have you noticed any specs (from any of the game lines) that share a significant number of talents, especially non-ranked ones? I wonder if it would be useful to blitz through a second spec by automatically gaining non-ranked talents already taken in a previous spec.

There are a lot, usually it's the talents with Improved and Supreme versions. One of my favourites is Armourer and Commando

Doctor and Medic are fairly close, both with the full Stim Application line. The Medic specifically uses it as a path down the tree, so taking them all in Doctor first is a good way to get to the bottom of Medic.

I'll take a look and see if there are any other good ones. Driver and Pilot come to mind as well, with the Full Throttle line. In fact...if you already have Supreme Full Throttle from them, you can take Racer and go straight from the 5 xp Skilled Jockey to the Force Rating.

Pilot and Driver are nearly identical. The main differances are that the right 2 columns of driver deal with fixing things and the right 2 columns of Pilot deal with astrogation and shooting. The left 2 columns have most of the driving talents (full throttle and so on)