Innovation Versus Formulaic Gameplay

[Koh]

That's exactly how I feel. Which is why I cite the transition of the first 6 Final Fantasy games as a perfect example.

FF1 was first, so there's nothing to say here.
FF2 changed up the gameplay style by making it so you level individual stats and skills, thus allowing you to tailor each character in whatever way you desire.
FF3 introduced the first class change system, with a lot of different jobs and abilities to use.
FF4 went back to fixed classes, but was more story driven and introduced the ATB system.
FF5 continued to use the ATB system, but introduced a more versatile Job and Ability system.
FF6 also continued to use the ATB system, but introduced Magicite as a way to acquire magic and more ways to battle such as Pincer and Side attacks.