The Stanzi / Christensen controversy has definitely been overblown over time - at least in terms of the length of the "controversy". Stanzi, a sophomore, played in the first 3 games, and did well. Against ISU, Christensen came in when Stanzi was off, and Iowa ended up winning that game, sealed by Brodell's punt return down the west sideline into the south end zone. The next game at Pitt was the one that I recall caused much of the controversy, where each played half the game. Stanzi was playing well, when Christensen, by design, played the 4th quarter and Iowa stupidly lost that game. That was the end of the split QB routine that year. Iowa lost 3 more games that year (by a total of 10 points or so) before getting hot and finishing the season strong. So the controversy existed for a short while, and arguably lost them a game. I do recall believing that Stanzi was the better choice that year, but Kirk was committed to playing this out in the non-conference portion of the season, sealed by the two performances at Pitt.
I don't recall McCann being excellent, but he was adequate. They won 7 games that year (and should have beaten ISU in that late season game delayed due to 9/11) for an 8 win season. I do recall some discussion about Banks not being ready to play a whole game given his limited knowledge of the playbook, but I don't know if that was cover for McCann or not. The Michigan game gave us a glimpse what Banks could do. The one play I remember from that game was him stepping out of bounds a yard or so short of a first down. I recall that he didn't come back in after that, and that had many fans (including me) wondering why we didn't see him again that game.