Okay, two updates. The Great Mouse Detective Mystery in the Mist DVD/BD are no longer recommended at all. I tried to watch it and found the over scrubbing to be a terrible experience. Certainly not worth the trade off for the 'cleaner' look and original title card. (I'm also not convinced that the new color scheme is any more accurate).
The Little Mermaid has been revised. Phew, it could now possibly be the longest entry in the guide.
I've given 3 'purist' recommendations only because everyone has their own opinion.
The Diamond Edition is being tentatively called an 'Acceptable Alternative' contingent on what is repaired in the replacement discs Disney is offering.
That said, I doubt they will be fixing some of their color/lighting changes or additional censorship.
Unless someone goes through and fixes what Disney doesn't and adds any type of theatrical audio mix, it will never be a purist choice. (Honestly, I'm having a hard time calling it acceptable, but you guys are.)
I don't know if this has been previously posted, but here is a good comparison of Diamond vs Platinum.