As a result, the pace of taking Dragon Utopias is roughly the same as for other towns – on average, end of week 2 or beginning of week 3.
I don't see any imba here at all. Yes, there are layouts where everything goes like clockwork – lots of chests, plenty of money, creature cutting goes smoothly, and by week 1 day 2/3 you're already dropping Utopias in batches. But that's very rare. On average, it's much more modest.
The statistics of games for Inferno in tournaments like RP confirm that. As does the fact that many players prefer to start with Fiona and handle creature cutting on an optional basis.