Brace height is much like using an over draw or standard hole. The overdraw is less forgiving as the arrow is still on the string when it's very close to the rest. this makes nock height and center shot spacing more critical. Also spine becomes an issue as your arrow isn't flying PERFECTLY when you release...there is ALWAYS SOME wiggle..no matter how small.
Look at it this way...if you lay an arrow on a table, and put another arrow perpendicular to the first, under the tip of the first arrow, the top arrow is still pretty level. now as you slide the lower arrow closer to the nock you will see the tip rise. the closer you get, the FASTER it will riser (Progressive vs. linier).
This is one reason drop away rests are more foirgiving than launcher style. and why launcher style are more forgiving than a solid mount arrow rest. (seen many wisker biscuits at Vegas?)
On traditional equipment, it isn't quite as big of an issue, as archers paradox has the arrow off of the rest (or shelf) long before the bow is at rest.
As for long draws winning Vegas...there are VERY FEW pro level archers that actually FIT a 28+" draw. MOST that shoot a long draw, simply are shooting TOO long of a bow. That and MOST guys with a REAL long draw, most likely got into OTHER sports for competition (Basketball? Football? Volleyball?). So the pool of archers to draw from is much smaller than what you would find in the shorter draw ranks. Yet somehow at the 3-d shoots people are always complaining about the great advantages of long draws, and how those guys should be restricted somehow (speed limits etc)