"Humor is often missing here."
Translation:Humor fehlt hier oft.
"Humor wird oft vermisst" means "humour is often missed" (as in people would really like it to be there, but it isn't). So it's the difference between simply being not there and being desired to be there.
'häufig' would work. The German sentence doesn't sound very natural to me. I'd rather say 'Hier fehlt es oft/häufig an Humor'
No, 'verpassen' means 'to miss' in the sense of 'to miss the bus'. It doesn't work here.