I think the TNG-HD idea sounds very nice.
Obviously the new special effects need to be done darn well, already because I still think that many of TNGs special effects have stood the time very well..and still look good.
I just hope they wont start redesigning all the ships of the show. I want the Romulan warbird
, Promellian battlecruiser
, Tin Man, Enterprise-C, Stargazer
and others to keep their desing..even though they would be made with CGI.
Replacing the Excelsior-class
with some other ship could be a good idea, but I would like to see it still in the show also, at least the USS Hood
should stay as Excelsior.