It's beyond debate that George
Lucas pushed special effects farther faster than anyone in the history
of cinema. While Episode IV: A New Hope was breathtaking for
its day, it was only the beginning. There is a clear and consistent
escalation in effects technology that is evident with each subsequent episode,
and part of the fun of watching the series was seeing where they could
take things next.
By viewing things chronologically, even
starting with the "Special Edition" versions of the trilogy, there is a
steady increase throughout the saga... with a notable leap forward into
fully-realized CG characters when one comes to the prequels. To start
with Episode I means lowering expectations halfway through the series.
While the original trilogy is movie-making at its best, viewers will certainly
miss the remarkable panoramas of worlds like Coruscant that are never equaled
in the original trilogy (aside from the brief Special Edition inserts tacked
onto Return of the Jedi).
The only visual surprise Lucas saved for
the original trilogy was smeared starfield of the hyperspace jump (first
revealed aboard the Millennium Falcon in A New Hope).
Dramatic as that was, it's very little compared to the modern digital capabilities
realized in the prequel trilogy.