Bo used to make completions into double or triple coverage - but his throws don't have a zip to do that right now (or maybe for good).
He used to have fantastic velocity and accuracy on his 10 - 25 yard passes, and that is just not there anymore.
From what I can see, his poor decisions come mostly from a lack of protection
And don't forget - teams have done well against him in the past, when they got some pressure, especially in the playoffs. Redblacks, Bombers, Argos - all come to mind.