I agree that this was a difficult choice; several years had a bunch of great movies. I ended up choosing 1984 because it has one of my favorite movies of the entire decade, “Amadeus”, plus several other very good movies.
I went with 1982 - just a slightly better collection of movies than other years. I really wanted to vote for 1984 (Amadeus!) but couldn’t because the other movies aren’t, imho, as good as the losers of '82.
Harder choices, especially since there wasn’t a year with at least one so-so film on the list. I went with 1980 for Raging Bull, but 82 is close (and would have won if it wasn’t for The Verdict (submediocre Oscar bait for Paul Newman).