When you know that your opponent gets to go last if it's your turn when time is called, chances are, you'll play faster on your turn to improve the odds that time will be called on your opponent's turn. I like that!
Regarding random seeding, at US Nats this year, #32 in Juniors was TristanR (2007 US Nats Champ). He beat the #1 seed in the playoffs, then proceeded all the way to the finals where he finished #2. TristanR proved that #32 in swiss is just as good (or maybe better sometimes) than #1 in swiss. So, I see no problem with random playoff seeding, even for every round in the playoffs.