I really like Chan, fans will always hate playcalling. it comes down to execution and Chan puts his players in spots to succeed. w/ that said I can't stand seeing backward passes on 3rd/4th and short.
While it's certainly true that execution determines whether a play call is "smart" in hindsight, it doesn't mean all calls are good, regardless of whether they work.
Calling for passes 2 yards short of the marker on 3rd or 4th down is poor playcalling, regardless of execution. The playcall that almost certainly should have had Decker alone in the endzone, rather than Kellen Davis, was a good call that was terribly executed.
I still believe Gailey is the best OC we've had in a very long time, but that doesn't mean he doesn't make bad calls.