There is absolutely no question that the Ninja Turtles game for the NES is quite possibly one of the hardest video games of all time. As challenging as the Ninja Turtles was for the NES it definitely was not a game that many people would have wanted to see a remake on for the SNES.  If the original Ninja Turtles game for NES was remade for the SNES but with reduced difficulty then maybe it could have worked out.  

However, Teenage Mutant Ninja Turtles: Turtles in Time for the SNES was still a way more popular title than the original Ninja Turtles game for the NES.  The beat em up genre suited Ninja Turtles games much more than platformer ever did.