Well up to season 4, the show was funny, not because it tried so hard as it does now, but because of the awkward moments in it. Like the dumb awkward things Michael says, when he thinks he's sounding smart.
I mean, Season 7 has it's moments. It's a lot better than Season 5 and 7, because they're focusing more on Michael. But when you break down the season, Michael is the only one who's been consistent, and I think it's the other people's characters that are making him seem less funny.
Michael: Guy who thinks he's the funniest and does awkward things.
Jim: Character who went to being a guy just working at Dunder Mifflin not wanting a career and playing pranks, now has a career at Dunder Mifflin and doesn't do pranks.
Dwight: Character who was always the whiney, goody goody who would never do wrong and was loyal, is now a guy who thinks he's the greatest person in the building.
Pam: She went from being the shy one, to being a more open outgoing one (to me I think she's gotten funnier.)
Phyllis: Who went from being that sweet grandmother that you loved, to just being plain annoying.
Andy: Went from being a character who was trying to make a name for himself, who is now trying to just fit in.
Stanley: Perfect every season.
Creed: Died down in the last couple of seasons.
Meredith: Went from office slut to just a prop.
Kevin: Awkward funny moments to trying too hard.
Oscar: Went from someone who thought he was better than everyone but staying quiet, to flaunting it.
Angela: Became a prop.
Ryan: Prop.
Kelly: Annoying character. Yes she's supposed to be, but it's too much. Trying too hard.
Daryl: Warehouse Guy to Office Man, thus making him follow rules now.