Actually, they didn't do a bad job.
I get the "remastered" episodes, but not in HD here.
The effects people have generally used a light hand on the effects, certainly lighter than Lucas used on the original Star Wars trilogy, and with the original untouched series readily available on DVD, I have no problems with people doing something like this.
"Ain't It Cool News" has been following these, and this article shows a typical rework of "The Doomsday Machine." Note how they resisted major change to the papier-mache star of the show. More shots here.