There are many games where each part of the series changed a lot, even if the devs were mostly the same.

What will really matter in the end is: it's the game fun? Including system X and repeating anything done years ago wouldn't guarantee success. The expectations today are beyond what was fine 20 years ago. Innovation means taking risks, and blending old with new it's always a complicated process, making it fit and somehow work together.

If we really want to look as "experts", at least those of us expecting things done in a certain way, then we should know that failure is a real option. Careful with putting too much pressure when things can go wrong anyway.