After the 4th or 5th movie and all the characters are well-established, then yeah time traveling can work. But time traveling an altered character to have him join present day existing characters is soap opera levels of convoluted mess. Will future Spider-Mex meet up with present day Spider-man, or completely supplant him in the present day universe? Most likely it will still be Garfield Spider-man who joins up with the rest of the Marvel superheroes, so keep dreaming.