Face wise she doesn't look aesthetically terrible. Objectively, I think it looks pretty good if you're going after a mannequin look. She looks devoid of personality and life. And that is terrible. Her original face had a lot of vibrancy and life in it, reflective of her voice and personality at that time. I actually think it's a bad example of plastic surgery because it doesn't tweak the face but rather changes it almost completely. The two images could really truly be two different people. Maybe mother and daughter.
Her boobs are ridiculous. She must have gotten stretch marks as a result.
Honestly, Spencer is the fugly one; why isn't he the one undergoing the changes? Oh yeh, because he's the puppet master...
Whether she's doing it to stay relevant/for the fame or because she's in an unhealthy state of mind further exploited by the manipulative relationship she's in, it's quite sad. It's probably a bit of both and reflects why psychological assessments should be mandatory for excessive plastic surgery. Although even if such assessments were mandatory, they'd be bypassed in Hollywood.
Ultimately, plastic surgery and Hollywood go hand in hand. So what Heidi has done is probably not that shocking and that's why she thinks it's necessary to keep up or just plain normal.