I'll mirror what Valor said. I was working on a tournament that was based around everyone having the new 1.03 patch.
The new variable visibility and especially the assault rules effected every custom scenario design and the bugs/glitches would have been incredibly difficult to get around.
Tournaments are very fun for the players but frustrating for the tourneymeister, in dealing with all the problems. The new assault rules and bugs/glitches would have the tourneymeister chewing his or her foot off.