There's also nothing wrong with wanting the best possible representation of those shows and films. TOS is very clearly a product of the 60s, new effects or no - and it looks amazing all fully restored and in HD. Modern technology marches on, and for that exact reason, I don't want to have to settle for old VHS-quality episodes when I could be watching it with amazing color and detail.
TNG will likely be the same. HD may reveal more of its flaws, but it'll still look way better than the current DVD transfers and I'll be the happier for it.