Very good post, and I definitely see your point about there being a vast number of LBs if they became model-specific.
However, I do feel that a simple option added to toggle between [top scores] [near me] [friends] and [
same car] in the main LB would make the world of difference. It would simply become a filter rather than an entirely new LB.
As for this, yes it does indeed take forever. I've made my way through classes B, A, S, R3, R2, R1 and half way through X so far. Taking me an age but I'm determined to get them all done.
Thing is, because there are so many of the little crappy tracks, I usually just do a single "flying" lap, rather than a flying lap followed by the actual fast lap.
I know it's costing me a lot of time overall, but I really can't be bothered trying to shave a couple of seconds off countless tracks like Iberian Mini, Ladera Mini, Test Track a, b, c, d and so on, plus all the reverse variants
When I start a class, I quickly go through all the dirge, and then put a bit of effort into the real tracks that are worth a bit of lapping.