Humour solves at least half the problems in any film, or at the very least, keeps things entertaining. The Fall Guy isn't above criticism, as you say, but it's a huge blast - funny, romantic, action packed, with great chemistry between the leads, and a great setting raising awareness about the stunt team and their invaluable contributions to film. What's not to like?
The unicorn gag had me in stitches by the way. :)