AC, over more than a decade, has provided first-class, all-star performance, year in, year out and the stats are there to prove it. He is, without a doubt, a HOF prospect. He may yet shatter records that may never be beaten unless an equally talented QB comes along; one who, like AC, has longevity in the CF. Has AC had off games? You bet! What QB hasn't? However, the quality of being able to rebound season afeter season is what has made this QB great. Having said that, however, AC is 38; he may choose to return for one more year or not and yes, there have been some "chinks" in his armour noted of late - that is to be expected.
There is no QB controvesy that I know of other than certain individuals making one. Most of us on this forum would love to see AD have more meaningful reps under center, and not just in garbage time. AD appears to have the right stuff, but, like AC needs time to develop his skills and that can only happen in game situations. His time will come, other things being equal (i.e. he decides to stay, AC retires this year or next...etc.).
As to your other point, Flag, you are quite correct. The great CFL and NFL teams have all been led by their no. 1 QB. There have been some exceptions here and there with a dual QB system, but that has been the exception, not the rule. Football, unlike other team sports, requires a field general, namely the QB. He is the de facto leader of the pack and inspires confidence. That in turn has a ripple effect not merely on O, but the entire team! While AD has definitely shown some sparks of brilliance, I don't believe he is at that point yet. To be sure, as AC goes, so does the team.
This Friday's loss can be summend up as a lack of focus, lack of execution, sealing 1st place with 3 games to go...etc. I sincerely hope they address these issues for the next 2 games.