At least now it's more balanced. Having 5 or 6 teams in a group and not playing in a round-robin format was just rubbish. And this will make the transistion into the next round much easier, as 50% of those teams will be gone and only 8 will be added.
I'm looking forward to Vienna v Celtic now - one thing I love about football is the fans' ability to hold a grudge for all eternity and constantly seek vengeance for a defeat. You just don't get that in any other sport, not to the same degree or intensity.