A polite juggler would be worthless. You've seen how few players vote in a server? That's how many would respond to Juggler requests.
Juggler must be aggressive. It just also must be *perfect*, or the aggression it displays will just be frustrating and stupid.
And it sure as hell ain't perfect.
But yes, focusing on players waiting for a game to finish would be a good priority. Being aware of which maps all players have before juggling them would be awesome, although I don't know it's possible - there's nothing worse than being juggled into a game, finding out we can't start because one player will be downloading the map for the next 10 minutes, and then missing the start for the old battleroom.
I don't get why we have this long delay between battles but the Juggler doesn't provide us with a way to get back to those battles - you can be juggled-out into a game that fails to start, but then miss the start of your old game too. Then you're stuck with 3 guys who don't want to play FFA. It's ridiculous that we're all "ooooh, you have to wait another 90 seconds for break"... but "hey, I just took a chance and tried to split this game into two games. Y'know what? I'll just assume that worked perfectly! You guys go ahead and start!"