After diagonal settings, anything would be an improvement! Seriously, there isn't any "rule" for placement of pulls or knobs. Could you post a photo of a section of cabinets? It would be helpful to see what your doors look like.

This is my dining room, aka room of curing doors. Only a hint of the size variation.

My kd had the bottom start at three inches above the bottom edge and the same with knobs. I like the pulls placed that way but with the few knobs that I have I would have rather seen the knobs a bit lower. I do agree that there is no right or wrong just what you prefer.