Tokyo Ghoul Root A is maybe not the AOTY 2015, but because I see it collects here only criticisms at best not very fair, I must restore the balance of the opinions.
I think the problem, above all, is the state of mind with which we perceive this second season. Indeed, in the echoes which I received from Tokyo Ghoul, there was hardly only of three sorts: "S1 is a little bit boring but in S2 it gets interesting", then "S2 is a waste which murders S1", and "S2 isn't canon compared to the manga since Pierrot has fucked it up". And indeed, we have in front of us 2 seasons with different rhythm which do not have much in common between them.
Personally, when we spoke to me about Tokyo Ghoul, in view of the name, the pictures, the first minutes of the first episode of S1 with a glowing Rize, and... a certain white-haired boy who can "no longer see the world", I imagined at once something bloody , violent, merciless; a persistent war between ghouls and humans until the annihilation.
As a result, I felt an afterstate of slice of ghoul life, in front of a S1 which has certainly its moments of cruelty and tragedy, but which gets mainly down to show us that ghouls are as the human. They too have their ties, their pains, their hopes, their despairs...
It was not what I expected, but it wasn't unpleasant after all. It is necessary to be immersed, this season is essential to blur the manicheanism, make us wonder ourselves of which side we take place in this war.
It takes sense only because we know the battle arrives. The last episode of this S1, symbol of its depth, justifies everything, and represents a transition towards a more bestial S2 putting an end in this "calm before the storm".
But let us bend over this S2. The answer is yes, it reigns a certain confusion... a certain lack of sense in the plot's structure. However, I would here want to bring a nuance: it's not inconsistent for all that. Those who didn't read the manga are certainly going to miss some information, and in order general the decisions of the characters are not clarified. But nevertheless, by making a little effort there, they can easily, and even with the few of elements they have, to understand what it takes place and why.
The biggest riddle, of course, remains Kaneki Ken, our protagonist. It's maybe the one who seems most emotionally weak at first sight. However, you shouldn't forget as far as himself, in the situation, is not necessarily capable of being completely rational, having lost its innocence. Even if he makes a little bit debatable decisions, it works. It's not a plot weakness, but a will to let the public think about cogs. His character developpement is memorable.
And then, it's a season much more turned to the action, with an anthology OST and a magnificent animation made by Pierrot which hits the score, and can show itself rather epic. The characters psychology is not aside left for all that, it's even more developed than in S1... But it's moved, expressed through flashbacks which often take 1/4 or 1/3 of the episodes (it's not inevitably a flaw).
According to me, without saying about it too much, THE big flaw of this season is the end: excess of doors left open, too many tracks which we would have liked seeing exploited throughout the anime and which are dedicated to remain unsettled; despite of a conclusion endowed with a beautiful staging. But I saw it in so many series, and especially I saw so worse than that, I don't see of what complain here. It's less hateful than the disease from which suffer so much animes when, in two episodes of the end, they begin to hesitate absolutely anything, to accelerate things and arrive at a conclusion, which besides making no sense, most of the time solves nothing for all that.
And now, it's time for the notation :
[Story part : 4/10]
.An average pacing, too slow in S1, and too fast in this S2. (0,5/2)
.A pretty good premise like S1, with an freshly enigmatic Kaneki. (1/2)
.Complexity isn't really present.. Too much focus on the protagonist. (1/2)
.Regarding Plausibility, there are some obvious plot holes. (0,5/2)
.A conclusion which makes diverge passions, and disappoints me. (1/2)
[Animation part : 9/10]
.Good production value. (2/2)
.Great use of shadows and darkness, good visual effects. (2/2)
.Memorable character design (Special mention to Eto. Spooky.) (2/2)
.Well animated (Especially to the end of the show)and very good staging. (2/2)
.A decent background, but there is a lack of details. (1/2)
[Sound part : 8/10]
.High quality sound effects. (2/3)
.According to me, an anthology OST (Special mention to White Silence which isn't integrated in the show : https://www.youtube.com/watch?v=NogZeIey-Jo... This is art.) (3/3)
.A great voice acting (Special thanks to Eto again...). (2/3)
.Good BGM, atmosphere is immersive. (1/1)
[Characters part : 8/10]
.Acceptable presence, especially with the main characters. (1/2)
.Very poignant catharsis, definitively. (2/2)
.High quality character developpement, in particular in Kaneki and Amon. (2/2)
.Detailed and deep characters personality. (2/2)
.Good but incomplete backdrop... (1/2)
[Miscellaneous part ( doesn't count in the notation ) : 7/10]
.Good Rewatchability. (2/3)
.Disappointing OP and ED contrary to S1. Just saying. (0/1)
.Enjoyment is here. It'll stay in my memories. (5/6)
OVERALL : 7/10