well, I think being frontrow for the Sing Or Die concert would have been just as good if not better than the westcoast tour, since it was lot longer and had all the real backing Japanese players like Koh. I don't particularly like the overly stagey stuff in WL, but I could tolerate it, and they do tend to go over the top so I almost think watching the WL's on DVD in a hometheater is just about as good as going in person, since there's so much happening so far away you're basically watching it on screen when you're in person too.
As for videos, I only have WL '95, SoD, and one of the WL '99 videos right now, so among them:
WL '95:
1) The entry, seeing them all emotional and jazzed up
2) Masu plucking his bass dramatically at the end of Kanashii Kiss at sunset, and the beautiful cloudy sunset that was seemingly part of the song. Can't get that inside an arena.
3) The dancers didn't do much for me but Sae Ebisawa's ballet moves during Suki were very artful.
4) The 'sexy' miwa set was fun to watch.
5) The fireworks pause in Ano Natsu no Hanabi of course.
Children of the Sun '98:
1) The Yorokobi no uta intro singing was of course impressive
2) Miwa seemed in a groove for the concert, Marry Me? and my favorite song ai-suru kokoro were pretty moving (though of course seeing the latter live (it was her last song of the set) was a better moment
3) Miwa and Rin really belted out the tampopo song. Very enjoyable to watch.
I can't really recall much interesting stuff in the DWL '99 video, but maybe the Snowdance number was interesting.