Because Reid has always been a great play designer but not so much a great play caller. Like calling a running play on 2nd and 14 when you don't have and haven't even used a run game for 4 years. There has always been a formula to beat Reid and once a team figures it out then all the other teams can copy it till Reid manages to create a new offense then the cycle repeats. NE figured this one last year, Lions showed it could still work but they just didn't have the talent to make it work, Colts picked up where Lions left off and then we just followed the now well beaten path.I don't really get the Andy Reid hate on the Chiefs board. Guess every team that struggles at times question their HC... a lot of posters there seem to have a long lasting problem with him. To me the Chiefs look like the team to beat in the next decade, if they clean up their OL. I have never seen so many open receivers as with Reids offense... if I wasn a Chiefs fan, I would be very happy with where the team is at right now, including HC.
Back to topic, I would start to call it a draw. Both can do things that noone else can, both will improvise and something great will happen. I wouldn't be surprised if both of them will be in the top 5 QB discussion every year, maybe top 3... maybe even a Brady/Manning thing...
In some ways Reid and BoB have similar issues which may be why they have had almost identical success since Reid got to KC. Both play to their strengths but refuse to acknowledge their weaknesses. I would love to have Reid as a HC designing plays with the understanding that he is not going to be the one calling those plays.