Eh, I'd take either. I'll admit badass Shawn was better, but at least emo Shawn/Angela-ssessed Shawn added some gravity to the show and added a foil to the increasingly ridiculous Eric and Jack.
That's true and I wish Shawn was on this version, but I don't know if it necessarily kills the show (which is already an uphill battle to succeed).
What Eric became is just the typical family show character augmentation. He became psychotic because he gained a bunch of weight and wasn't the "heartthrob" anymore. There was so much melodrama with Shawn and Angela the silliness of Eric and Jack was almost necessary.