They're doing that stuff solely because it doesn't exist in a form that will translate to HD. The model work will.
Is this desire to "fix" stuff a Trekkie thing? Are there blu-ray forums filled with people wanting Alien or Total Recall or Tron fixed up? Special Editions don't really seem to fly. The Star Wars fans seem to get that now. ET 2002 won't even be on the new BR disc. When I personally watch a BR movie or see it again in the theater I'm doing it because I want to see what I've been seeing in SD in a sharper form. I don't want to see something new. If I wanted to see something new I'd watch a new movie. Does that make any sense?
2012 effects added to TNG will look as bad as the original stuff in ten years time (if not in ten minutes). If the remasters are eventually going to look bad, shouldn't it be with the original work in it?
Well they've already replaced a few model shots (like during the saucer sep), and most people seem to love the new planets, transporter beams, LCARs, and other little touches.
Are you saying you really want to see the original, heavily pixelated versions of THOSE effects superimposed over this pristine new footage we're seeing? Those would stand out like a sore thumb, and look frankly ridiculous.
While I did think some of the new TOS-R shots got a little too flashy and sophisticated, I have no problem with updating some of the more badly outdated effects-- mainly because A) They're only effects, and B) I'm much more interested in seeing the story told as well as possible.