Character wise, emotionally speaking, the finale was real good, sad characters you cared about and that has been so well fleshed out throughout the seasons having their peace of mind (several genuinly tear jerking scenes). Its the mythology and analyzing and answering of the plot mysteries that fell flat in the finale, you know, lacking closure in a minor thing called story (though defenitely closure for the characters).
Actually I didnt expect them to tell that at all, so I wasnt dissapointed in that regard alone (I came to terms with them not doing that long while back when I realized they were rushing it, and was dissapointed then), I expected a good vs evil duel as we saw mainly. But whats dissapointing, and many people have commented on, is they said even if we disregard lack of answers due to the emotional content of the finale, whats fucked up is the cop out that is the last 10 minutes (essentially last 30 mins in a way). Its really a lazy ass way to cap it all, thats without any doubt. So uber vague and blaze, to have it all be somekind of middle passage between death and afterlife, walking to the light.
Thank God I truly enjoyed the ride, pretty much almost every second of it (never will be anything like it again), because otherwise this last bit would totally ruined the series for me otherwise. But the characters are way too good for that to happen, essentially they are what matters most of all.