I understood the scenario you meant, and the answer is the same. If you can see the rear beams of a vehicle, you should not use any high beam, period. Because it's dangerous and that's the reason it's illegal (in any civilized country). High beams, even regular ones, are more powerful than rear beams. If you can see rear beams in front of you, you can be sure your high beams are going to be noticed. Also, you have to understand than what we see from the rear driver's point of view is the light that has gone forward and bounced back. So, it's double the travel, something that dims A LOT the light we see due the inverse square law. But the driver in front of you is going to see the light WAY more strong than you, reflected to his face on the mirrors.
That's why it doesn't matter that we THINK the vehicle in front of us is far enough and the high beams seem to lighten it only "gently" if at all, you NEVER use a high beam if you can see vehicles in front of you.
That's IRL of course, in the game the AI don't care so much about that. But SCS could do it, after all they already detect it (the cars flash at us when crossing them using high beams); and they could decide to activate a fine about it (I could imagine the roar on the forums if they ever do it
). So, that's why I don't think they change the fact that high beams are all activated at once. Although I agree that it could be nice to get rid the F4 menu for some things. But essentially what they had to do is to finally accept key modifiers (shift, control, alt) on the key mapping GUI (it can be done only manually editing the config files). Because we really ran out of keys time ago and new additions (like the suspension one) only worse the problem.
It could be nice also that the lights selection config could remain through saves; I stopped caring about use that lights bored of having to re-activate them every time. Or at least in the past that's what happened, if they fixed it I really don't know because I don't use them anymore for what happened back in time.
Regards