Videogames arent like other art mediums where the final product must reflect the vision of its creator only they must also appeal to people because videogames are both art and entertaiment.

I will take FFXIII as an example: The game had been created solely based on storytelling and on the vision of the team with their mindset "it becomes difficult to tell a compelling story when you give too much control to the player", and it shows in the game where gameplay was added just because its a videogame and had the FF name so it had to have some rpg elements. I wouldnt had a problem if it were a completely different game but it was FF and the most hyped of the series after FF7 and in the end we had a game envisioned as the creators wanted on some extend but we had a mediocre FF tittle, people that see games as a way to tell a story were okay but the average player and most FF fans didnt enjoy it because in the end is the gameplay what really matters to them and me.

In P4 case the game lives up to the wish of the creators and not on the players like you imply. The series are created based on that the character is you the player instead of the other way around, and so thats why they use a silent protagonist because they want to create a game where you can fill the role and enjoy a different kind of immersion, when the next Persona comes with a personality type MC then you can truly say that the creators didnt create the game as they envisioned but to appeal to the gamers, and i enjoy very much they concept because thats the kind of immersion i want, i choose how the story develope they not give me a fixed name so the desicion is entirely up to me, they dont give the MC a personality because is up to me to how he will act. For relate porpuses you have the other playable characters, to fill porpuses is the MC.

In the end it comes to preference when you play a game, wheter you seek story more than gameplay or the other way around. But for me a game has to live up to my spectations first and then the creators because thats how the videogame entertaiment works, im not opposed to heavy story games, im looking forward to play Heavy Rain because the narrative looks great and i like the desicion making of the game but i want my favorite games to offer me gameplay and then story, and more importantly CONTROL.