This is a very, very bad idea.
Such a vote would by definition be dominated by whomever could vote together as a bloc.
And, let's face it. A voting bloc in UO would consist of the biggest guild, and the biggest guilds on most shards I have experienced are the ones most-associated with griefing and other bad acts. No voting bloc based on justice, moral right, and reasonableness will ever triumph in UO. Ever. The most we can hope for is the lack of a bloc for the opposite.
There is also the issue of voter fraud. Voter fraud has been an issue in Faction Commander elections for awhile now, the creation of dummy accounts is one method, as is the temporary Factioning of non-Faction characters. Now imagine the voter fraud in a Shard-wide election!
I could go on and on and on with similar issues.
Now, if you looked at these and thought "what's the issue there," then there is nothing I can say to you on this issue. Our frameworks are too incompatible.
One thing not specifically related to the issue of an election, though, is the following: The overall leadership of the main maps in UO should, I argue, always be consistent across shards. Our characters' stories exist along at least two vectors: Our individual stories (and those of our friends, guildmates, enemies, etc.), and the overall meta-fiction "epic" storyline. Those should, I feel strongly, be consistent across shards and by definition this would include who the leaders were and what kind of leaders they were, at least in broad strokes. (I consider this separately because this relates to however they choose the leadership, election or not.)
-Galen's player