If/when the show is retooled to be more like the movies.

[neatoman]

Hey remember when the Fred Wolf cartoon scrapped the rounded big eyed designs in favor of something that kinda looked like cross between the movie designs and Eastman's style? As well as giving the show a darker tone, removed the goofier major characters and added clips from the movie into the intro?
http://fc04.deviantart.net/fs70/i/2013/253/2/d/tmnt_pissed_off_by_yifle1-d6lrn2u.png


And when the show was replaced the very next year by Next Mutation, a live-action show that seemed to more or less be intended as a sequel to the movies?
http://static1.squarespace.com/static/51b3dc8ee4b051b96ceb10de/t/532b2026e4b0ccd5fa53e90b/1395335209111/venus-de-milo-the-forgotten-female-teenage-mutant-ninja-turtle-header.jpg

And when Back to the Sewer redisigned the Turtles, Splinter, April, Casey and Karai to look more like they did in the 2007 movie?
http://th04.deviantart.net/fs36/PRE/i/2008/281/a/a/Back_to_the_Sewer_Awareness_1_by_IamTheS.png

Or a non-TMNT example that is much more recent, you know how Avengers EMH Started out with designs that mostly looked like how the character's looked in the 60's/70's, but then the second season made them look more like the do in the MCU? And how in turn EMH got cancelled after it's second season, to be replaced by Avengers Assemble which is meant to be clone of the MCU from the ground up?
http://www.medinnus.com/AEMH/images/roster_season_01.jpg
http://www.medinnus.com/AEMH/images/season_2_logo_02.png
http://img1.wikia.nocookie.net/__cb20130713150545/marveldatabase/images/5/56/Avengers-assemble-post.jpg

So yeah, you know damn well where I'm going with this (you read the title). If the movies continue to be even moderately successful (and they probably will), it's very likely executives might push for the show to be more like the movies.
Of course, the real question here isn't really if they'll do it (but "if" is still a possibility), but rather when and to what extent? Assuming the show does last beyond season 4, you can expect it to start in season 5.

The most obvious changes would be the visuals, the Turtles probably won't be made into giants like in the movie but it would not shock me if they start to wear the personalised items, or April starting to wear that yellow jacket. As for changes in writing, I don't think they would start to retcon several important plot point but would change the direction and some characterisation. As an example, I don't think they would try to force some retcon that reveals Splinter was a lab animal rather than Hamato Yoshi mutated, but I think they might be forced to alter his personality to resemble the movie character more and much of the direction of his character arc would be changed.

Of course none of this may happen, just be prepared that it might...

[Candy Kappa]

If the show takes a direction closer to the PD universe, I'm out.

[neatoman]

If the show takes a direction closer to the PD universe, I'm out.

"You know what would go great with a Crognard marathon? Orange Crush and Pizza Hut, brah!".

Yeah it would be pretty horrible.

[Sabacooza]

That would be horrible. Why mess with a style that already works?

[Luckyday]

Is Splinter from the movie any different then the one we have now? Although I really don't want him sporting a testicle top knot or wear that obnoxiously yellow robe.

[CyberCubed]

They won't do that. Nick clearly wanted their 3 new universes to remain separate from each other (Nick, IDW and the movie).

[IndigoErth]

Given the medium I doubt they will do any redesigning of this one. That's far easier done with traditional 2D animation.

I could see them either
a) doing a second series at some point after the first, as an older continuation for a slightly older audience with older, less innocent/childlike looking character models, and money saving reuse of already existing environments.
..or..
b) doing an entirely separate TMNT in 2D based on the 2014 Turtles if they decided to do something with them.

I've seen some decent fan art for 2014 that if inspiration was taken from those... it might be decent for 2D. (And avoid that app game's art style, please.) Would really not recommend 3D for them... would have to cut down too much on the quality and detail to make it even affordable, a cleaner 2D design could produce more visually appealing characters imo.

[jenna]

The difference between the "Red Sky" and "Back to the Sewers" redesigns is that their respective shows had all but lost momentum. The OT was 7 seasons gone and the turtlemania hype had passed and people cared more about The Simpsons; 2k3 had been through several attempts to reignite it after the slump of banned episodes, declining viewership and an unaired season. They tried Fast Forward and it didn't strike a chord, so Back to the Sewers happened.

Redesigns are a sign that the show is making a comeback attempt - and if they have to resort to piggy-backing on the success on other incarnations it's a sign they really are out of original ideas - and probably is the beginning of the end.

I don't think we are anywhere near that point with Nick. If it happens it will be when the show is attempting to claw its way back from the brink of cancellation. Nick is strong. It does not need to blend with the PD universe to survive. If anything, the producers would probably recognise that it would be detrimental to the show.

[neatoman]

Given the medium I doubt they will do any redesigning of this one. That's far easier done with traditional 2D animation.

I could see them either
a) doing a second series at some point after the first, as an older continuation for a slightly older audience with older, less innocent/childlike looking character models, and money saving reuse of already existing environments.
..or..
b) doing an entirely separate TMNT in 2D based on the 2014 Turtles if they decided to do something with them.

I've seen some decent fan art for 2014 that if inspiration was taken from those... it might be decent for 2D. (And avoid that app game's art style, please.) Would really not recommend 3D for them... would have to cut down too much on the quality and detail to make it even affordable, a cleaner 2D design could produce more visually appealing characters imo.

Considering they have no problems only using characters once, I don't see that as an obstacle.

[Cryomancer]

THe 2k3 retool was obviously movie inspired, but I don't know that Red Sky really was. It felt more like it was 90 comics inspired or something, or maybe second-hand comics via the X-men cartoon.