They both suffer from serious problems, but not the same problems.

The Hobbitses just have poor editing. Chop ~70% of the movies away and suddenly what seemed like crappy writing or over-reliance on CGI at the time would just be revealed to be the sort of uninteresting filler that would have been edited out under normal circumstances. I'm sure if nothing was ever cut from the Lord of the Rings Trilogy, it would have fared no better.

The PT, on the other hand, has crappy writing, crappy acting, crappy directing, crappy CGI, mediocre music, boring sets, poor editing, etc. It's not just bad, it's really a whole different level of awful.

Both, I'd agree, are symptomatic of creators operating without any outside checks on their ideas, or they'd have never seen the light of day.