I think the simpsons is basically absolute trash now. Older simpsons were somewhat serious with goofy yet still awesome plots (like the the spoof on Citizen Kane that had the 3 eyed fish and Mr.Burns running for governor). The animation has become worse, the voice actin has also slumped with characters like Barney, Nelson, and the most recent addition Wiggum.
Another big problem is the annoying and constant use of celebrities on the show, usually they don't add any humor at all, most of the time they are a huge waste.
And it just isn't funny. I haven't laughed out loud at the Simpsons in quite a few years, while the old one's never fail to entertain me.