Why Rise of the TMNT is a total failure?

The answer is really simple:
The people behind it don't understand what IS Teenage Mutant Ninja Turtles.

"They all look different"

Let's look at the Turtles Prime incarnation...

Similar build, all red masks. If it wasn't for the weaposs, you wouldn't know who is who...

Strike hard and fade away into the shadows.

It almost sounds very ninja like. Striking from the shadows, while looking similar would create illusion of a larger number of ninjas attacking OR that it's ONE super powerful demon turtle ninja.  And yes, the 2012 series also failed here. Heck even the 2003 and 1987 failed here with the colored bandanas.

Hamato Yoshi did not die/ got turned into a rat to have a failure of a ninja army...

"They are learning the ropes."

Load of crap.
Again: Hamato Yoshi did not die/ got turned into a rat to have a failure of a ninja army.
Splinter has LITERALLY RAOSED THW TURTLES THEIR WHOLE LIFE. 10+ YEARS OF NINJA DISCIPLINE yet these turtles behave like spoiled brats.
Depending on the continuity the turtles are either:
Trained to Avenge Yoshi, or trained to protect NYC from the Foot. 10+ years of training while starting on their formatove years would yield a much more disciplined breed of teenager. Perhaps an even more mature breed due to their knowledge of assassination arts.

Case in point. Mikey was acting without the proper composure until Splinter simply said: Michelangelo, go!
Mikey went and did his punishment flips without any sass, snark or anything.
That kind of discipline is lacking on Splinter and the turtles. If 10 uears of Martial arts don't give you discipline, then you suck as a human being  (or turtle)

"They behave like teenagers"

Worth repeating once more:
Hamato Yoshi did not die/ got turned into a rat to have a failure of a ninja army.

I mentioned the discipline aspect before. Now I'll mention their personalities...
THEY ARE NOT ALL SHADES OF MICHELANGELO.

This is something most series have done well. 2012 has been amazing on this regard. They did behave like teens, had discipline AND independent personalities.

Leonardo struggled with the burden of leadership as he was chosen to be the leader. More of that struggle with himself for not being the leader he THINKS Splinter wants him to be with a brother who'd rather goof off, another who'd rather work on his experiments, and one who question his leadership and thinks because he's the toughest, he'd be a better leader. Seeing Leo's journey into making his brothers the team needed to avenge Yoshi or defend NYC from the foot. Habing a visible power struggle between Raph and Leo with Mikey and Donny following each of them at times until Leo finally proves himself as leader.

Raphael's tough warrior/angry loner arc, we've seen a million times. (Especially with short, angry stabby Canadians) but since we're doing a new TMNT, we need to see it once again. Raph's journey to channel his anger, seeing a waeped mirror of himself on the self-proclaimed vigilante Casey Jones. Both of them struggling with their rage demons until they find a way to channel that anger in a more effective way.

Donatello and his struggles with the physicality of their mission and his limitations (both real and subconsciously self-imposed) that force him to rely on gadgets. The journey of self discovery that teaches him the truth about man and tools... the tools do not make the man, the man makes the tools. The most powerful weapon in Donny's arsenal is his brain and all that.

Last but not least, Michelangelo, who'd rather have fun than working on "the mission". Perhaps exploring the idea that Mikey MIGHT BE a sort of pacifist or a reluctant warrior kind of thing. Mikey's journey would basically be one of accepting that full on pacifism is a fallacy.  Violence is not always the answer, but sometimes there is no other choice.

Let's see what we have here: journeys of self-discovery where the turtles and kids will learn about themselves.
With Leonardo, to put the well-being of others before oneself and do the right thing, even if it's the hardest thing to do.

With Raphael, that cooler heads can prevail over hot tempers. To channel anger through other venues that are not destructive. Perhaps even learning WHEN NOT TO FIGHT.

With Donatello, the idea that while technology is a great tool, we cannot solely depend on it. Exercising the body AND the mind is the best way to improve oneself.

With Michelangelo it would be the opposite of Raph. And some of you would try to say that thwy are contradicting lessons... you're partially right. The real lesson is ACHIEVING BALANCE..

"You hate April because you're racist."

No, I hate April because they deviated of what she was meant to be and ruined her beyond redemption...
And 2012 made the same mistake to a lesser extent.
April is NOT a peer to the turtles. She's a sort of a Mother figure. Obviously, Splinter is the Father figure and Casey well, he's the lovable loser Cool Slacker uncle.
If you needed peers for the Turtles there's:
Carter, Zack, Keno (all of them diverse in race and personalities) and if you needed a Girl, we have Shadow Jones. Which would also lead to some interestingcharacter development. Having CaX7sey as a single dad trying to raise his daughter AND do some secret street cleansing at night. Meanwhile his daughter secretly hangs out with the Turtles.

"You just hate change"
I ran out of facepalm reactions... It is NOT that I hate change... I hate STUPID CHANGE and RotTMNT is full of it.
But the main reason is that EVERYONE IS A JERK in this series.
Suddenly Coming out of their shells and Christmas Special seem like better TMNT than this.