Could LP loss be a little based on grade?

Here's a revolutionary idea:

If I consistently am earning S's, A's or B's in those games where an assassin gets stupidly fed, and am hovering at a 50% winrate due to disconnects, sheer feeding and lack of team cooperation, shouldn't I be less penalized for losing than other people who are the source of the feeding? If the purpose of ranked is to seed players according to their actual skill level, then you penalize players who have legitimately improved, as I think I have, when you give them equal MMR and LP hits for games that they did extremely well in and were just unable to kill the Nexus for one reason or another.

Examples: I just played an Ashe game in which last pick got mid, troll picked jinx, was apparently playing on a friend's account and proceeded to give caitlyn 8 kills in lane while I barely held my own against a Viktor mid. I came back to earn an S-, carrying my team and stalling out as long as possible, but still take a 20 lp hit for a situation I cannot control. I understand that I simply need to carry harder, but I believe I cannot be the only one running into such difficulties on a regular basis, and MMR and % chance to win should not be the only factors that determine how many LP you lose.

At the least, I'd love an explanation as to how ranked believes me to the be the same caliber player as someone who feeds off and on most games. I'm not complaining about "elo hell" or anything, I'm just concerned that the current system does not accurately measure skill level.