-Ciro's designs were largely influential to fans & industry alike as they became points of reference for other iterations
-Helped to make Utroms & Mighty Mutanimals more commonly known entities
-Attached a bunch of stellar actors/voice actors names to the property which in a way validates TMNT as being something worthy of big names
-Pushed boundaries in terms of violence and censorship skirting, had character deaths despite being aimed at youth
-Proved you can recycle turtle talent (by bringing back Paulsen, Rist, etc.)
-Gave a certain demographic some acknowledgement for the first time (the sort of fangirls who crush on and/or ship the turtles with female characters) *
-Japanese language is used at times
-Original characters that have a lot of potential for future use
-First universe to make use of Tatsu since his debut (barring a brief boss fight in Hyperstone Heist)
-Montages with psychedelic visuals
-Visually distinct builds/head shapes/eye colors/etc.
-Alternate weapons for Mike & Don
-Leonardo has a geeky side
-An origin in which Saki/Yoshi's relationship begins as a close one
-The return of the Fred Wolf cast for the first time since that series ended
-Stories with different armors/costumes justified the necessary evil that is the variant toy
*Not really a fan of certain things that transpired as a result of this *cough* Mona/Raph stuff *cough* but I respect that they gave a very real portion of the fan-base some pie
I could go on...
