LP Gain/Loss and Game Length

It seems to me that the current method of LP distribution is a little backwards. Longer matches give more LP, however, it seems that more often than not a long match means the match was hard fought by both teams. A good, hard fought match shouldn't end in an increased loss/gain of LP.. it was a close match - if anything you should earn more for doing well and finishing quickly, not the opposite.

As such, I propose that LP start at a high value and decrease as game time increases. Better players will advance more quickly and those that are close in skill will slowly advance as the gap in their skill level becomes more established.

Some of you are going to say "But wait! If someone AFK's then it's 4v5.. it's not fair that we lose more LP cause of that!". No.. it isn't. So institute some LP protection in such a case. if a player DC's for more than 3 minutes on either team - LP gain/losses would be decreased 25% (or ___% after testing).

Thoughts?

Edit: Or perhap parabolic LP distribution. High LP for early ending and late ending games and decreased LP in the middle.