User blog comment:Rassilon of Old/Ep. 124 "Performance" discussion/@comment-3337007-20120408164604/@comment-4991912-20120408185042

I think they did it this way because season 1 was probably seen as the "establish the team" season, where they want to get as many issues out of the way as possible before the "invasion" hits, then really test the team's resolve as season 2 steams on.