Honestly, I generally don't eat that much dark meat from Turkey, at least not right off the turkey at meal time... I usually eat dark meat more, in leftovers... So, I don't have a lot of experience with texture and appearance of legs and thighs at lower temperatures... also, typically in my past whole bird experience , legs and thighs typically are already at higher temperature than the thickest part of the breast, so I can't say as I've ever actually seen or eaten a leg or thigh that was much bellow 165F.
The whole time/temperature for texture itself, is something that really intrigues me. Now that I have the ability to do sous vide, I think I can potentially learn a bit more about it , through experimentation... for me, I have much less desire to figure it out for poultry, than I do for beef/pork. Actually, I'm most interested in it as it relates to beef brisket. I've had too many dried out briskets due to waiting for them to probe tender. I've tried wrapping and don't care much for it... I don't like the fact that it makes bark become mushy, or that it stops to form all together... and I'm not convinced that when you rapidly go from 165F to 205F, that the connective tissues actually have time to breakdown... So, again, I myself am much more interested in understanding time/temperature's effect on beef connective tissue, than I am about poultry.