I think my biggest gripe (aside from not releasing the original versions as a companion to the SEs) is that for all their 'flaws', the original versions presented a consistant level of special effects technology throughout each film. With this new v.4 of the trilogy, you'll get a 1977 special effect, then an already dated 1997 one, then something added in 2004, then something added in 2011. They're just a Frankensteinian technological/FX mess now and it's THIS aspect that actually takes me out of the films everytime.
The original versions felt organic - the new ones feel cobbled together and patchy.