Hey man, this is a great article but I think you are missing two points, Dynasty warrior games are in general a re-skin, the mechanics don't really evolve that much but I do see where you are coming from mentioning them and agree in a way.

The other point is that Blizzard has been allocating resources to the "monetized" portion of the company ever since Activision came along, and that's the reason you don't see any more diablos, the original creators of diablo have said many many times that's why they left and that's why we won't see diablos in the near future.

Additionally, they now have to compete with PoE which is free and super high quality so that's something that will discourage the company ever further from launched a game that's not near perfect at least.