Personally, I don't think they ruined anything. Some of the images honestly look better smaller (though Divine Wings definitely deserves full CD-size).
LOL, Thraxz...I actually did do that one time, and one time only.
This was after I'd just heard The Odyssey and nearly decided I didn't like the band based on the one album. I was sorting through CD shelves one day when I laid eyes on V. I didn't know anything about the album, but boy did the artwork ever catch my eye! It was also very helpful when I turned it over and realized that it was a full-length concept album. So I ended up buying it...and sure enough, when I played it, I loved it! And from there, I was a real Symphony X fan.
I've noticed this too. It probably has something to do with their dedication to art. If they were making music solely to entertain people and cash in (as is the case with most mainstream music) they would certainly not take the time to make awesome cover art.
Also, if one doesn't have the attention span to listen to, and appreciate progressive music, they're hardly likely to pay attention to any of the details in the cover art.