The problem here is the plot. We start with DC and Peppone both "trapped" in Rome - DC in the Vatican, Peppone in the Senate - and both grabbing the opportunity of a small local conflict to hurry back to Brescello. So, the opportunity for fish-out-of-water gags is wasted and the first 15 minutes do exactly nothing to further any plot apart from setting up a running gag (both remain at home much longer than planned, thinking up every kind of excuses not to return to Rome).
Back in Brescello, it's business as usual, quite literally: Many of the episodes are just rehashes of similar ones from films 1 & 2. There's little tension and few (if any) surprises; every subplot develops as expected.
Summaryy: While the film feels like a nice old acquaintance, it fails to hold my attention or bring something new to the world of DonCamillo.