Maybe it's not so much the casting. 1941 does have that off-putting, slightly mean-spirited (and by that, I don't mean the same thing as intentional, purposeful "dark comedy") tone to it that almost all Landis comedies do. With Landis, there's often far too much relish in the mayhem he causes, and not enough moments of simple joy or humanity to compensate - much less any poetic justice. That's not to say I can't overlook this tone in some of his best - such as "The Blues Brothers". But Landis' comedies are total anarchy. (e.g. One moment the Blues Brothers are running the Illinois Nazis off a bridge. OK. The next, they steal from a hapless gas station owner and naive patron, and then completely destroy his station with a carelessly discarded match. Why?) Maybe it's this tone you're really associating with Landis?

There are other comments about what kind of film this would have been if Landis or Zemeckis had directed; but at the end of the day, didn't these film-makers take their cues from Spielberg? They borrowed from him.
Don't eat the whole ones! Those are for the guests.