Well, that should be the only answer to just how "important" a critic's opinion really is. A critic is allowed to dislike a piece, even vehemantly so. It means nothing, however, other than the fact that THAT person (as I believe music critics are still considered "people"?) disliked it.
So who gives a crap WHAT music critics think? Most of them don't have music degrees of any sort. Most have only read books by other people and are basing the very reason for their existance on the opinions of others. Most haven't even understood what the hell they read.
Just think of this. I don't mind what they write about me, as long as they write about me......... and you are not alone in this world. Mozart, Haydn, Vivaldi, Brahms, Schumann....... and now Matthew. You are honoured with this company.
There is a wonderful book that will put this in perspective (it certainly did for me). It's entitled "Lexicon of Musical Invective" by Nicolas Slonimsky. The subtitle is "Critical Assaults on Composers Since Beethoven's Time." Believe me you are NOT alone. The book is a hilarious read and includes every composer you can think of from Bartok through Webern!
The first review I received as a performer was on the, I kid you not, obituary page. Wedged in between, "Kintson man pinned in wreck", and "GM Executive felled by heart attack" was the review of the concert I had just given in Raleigh, NC. I survived - so will you! It's one person's opinion, and unless you read the paper that day, an opinion that didn't travel very far...