Interesting post, I've been thinking about this too. There's a lot of stuff you can learn that doesn't really take you in the direction you might want to go. Sometimes the desire to learn as much as possible can become a diversion, because learning indiscriminately can lead to the most relevant or useful knowledge for a particular musician's needs not being as highly prioritized as it should be.
I've been thinking lately that I don't need a teacher for lessons, so much as something along the lines of musical mentorship. For that, I'm going to have to seek out musicians in the area who I've seen perform live, and not necessarily guitarists.
Getting back to your post, here are a few thoughts: 1) You might not need a guitarist; 2) Jazz folks really know their music theory, esp. with regards to harmony and improvisation, whereas 3) Classical folks know theory as well, but skewed more towards composition and counterpoint. 4) If someone can perform (either in the sense of play or compose), they might not be able to teach well, but at least you'll know that they're not "the guys who just have an "advanced guitarist" lesson plan." However, 5) Some people can do things very well, but are terrible at explaining them. That's why Bob Ross is awesome. Whether you like his painting or not, he's great at teaching-by-communicating-his-experience.
Something else to think about: What you referred to as "goals" is a blend knowledge and skill (know-how). The "know" part can be taught/learned. The "how" part, the application of the knowledge - that comes with practice. At some point, and with some goals, the best a teacher can do is point a student in the right direction. I don't know anything about transcribing, but as you suggested, that might be the case here.