I watched from day 1 to the very end, breh I distinctly remember the SOHH thread and a lot of nikkas were mad at the finale and started getting tired of the show towards the end. Thing is, SOHH/the coli isn't really a good representation of the consensus opinion.
according to http://www.thebiggestboards.com/, i was posting on the 4th largest forum at the time. i'm not gathering my consensus from sohh
LOST was a pop culture phenomenon when it was on. Everybody and their mom watched it and everyone had their own theories and shyt that they loved to talk about everywhere. The finale wouldn't be so polarizing if people were only watching cause they invested time into it. People legit cared about the show during its run. Cats can't look me in the face and tell me they didn't care about the characters on that show. I remember cats legit sad over certain deaths. The flashback episodes always got rave reviews. Because people cared so much is why they react so strongly one way or the other when it's brought up. I'm not making up these reviews raving about the finale, brehs:
http://www.ign.com/articles/2010/05/24/lost-the-end-review
http://www.avclub.com/review/the-end-41436
http://usatoday30.usatoday.com/life/television/reviews/2010-05-24-lostreview24_ST_N.htm
http://featuresblogs.chicagotribune.com/entertainment_tv/2010/05/lost-finale.html
and that buzz you're talking about died long before the show ended.
dont have the ratings for s6 but it was lower than s5, so come on. #s dont lie. LOST came very close to getting cancelled. also, you can pull put those 4 reviews all day, but if i really wanted, i could find 10 negative LOST finale reviews for each one of those.