Okay, maybe that's true to some extent. Flutie was not an elite QB, but he was much better than Johnson. Look at the following season when Johnson had the majority of the starts, the Bills were 8-8, Johnson was 4-7 and Flutie was 4-1. Also, the season afterwards, when the offense was suppose to be tailored to Johnson's strength's, he only won 1 game in that 3-13 season.
Yes we had a great defense a and QB (Flutie) that did just enough on offense to outscore the other teams. Well, I'd rather have a QB that just did enough to win us games, than a QB that couldn't stay healthy and could barely win games (Johnson). Bottom line, the QB switch cost us the playoff game vs the Titans and possibly a trip to the Superbowl that season.
One final point on QB's that just did enough, a perfect example of that is the 2000 Ravens with Trent Dilfer. I'd take that anyday over the garbage we've seen from the Bills this decade.