Just one problem with your way of measuring balance. When teams switch sides, so do the win counts. So even if settings heavily favour Blu and they win 100% of the time, the scores will look pretty even because it will show as Red after teams switch sides. They were 31-31 this evening with vanilla respawn times even though Blu won more often, and that's just one example - the numbers are rarely too far apart for this reason.
That being said, I do concede vanilla respawn times favour Blu, but turns out most of us enjoy it more like that anyway. Third stage is usually a challenge for Blu to cap regardless.