The over the back view had been done a lot earlier in games than Resident evil 4 my friend. I don't really think its all that much more innovative than Devil May Cry. You do practically the same thing in both games, the only difference is Dante can fly around, while Leon is more grounded.
It was FUN, but it wasn't like RE3 was dull. It did have the wandering AI boss continually chasing you around after all.
To me, its a radical departure from the rest of the franchise. Its good no doubt, I still consider it an 8.5/10 game. I just don't like it as a RE game. It was so cheesy, it had no elements of fear to it, it was easy, and series staples like zombies/umbrella make no appearance. You don't need to get rid of them, just make them behave differently if you think that zombies are getting old. Its almost like they took the idea for one game, and slapped Ada/Wesker/Leon skins over their main characters.
Continuity wise it also hurt, instead of going straight after Umbrella, there is always going to be this one cheezy episode where Leon had to face Los Plagas.