I'll take your word that a wRC+ of 86 is above average for a LHH vs. LHP...although I must say that is a little mind blowing. I guess they typically crush RHP, but that stat is one of the reasons I never got the infatuation with having LH/RH balance in a lineup....So many LHH are relegate to being a Ryan Goins type hitter late in games - even by underwhelming LOOGY's.
Personally - I prefer to look at the past 2-3 years when evaluating players because, well, players make adjustments. It's like looking at Russell Martin's career average and expecting him to hit .255 this year.....not going to happen.