Honestly, The Simpsons should've been cancelled a long time ago, I can barely stomach anything post-season 15.
And FG, what can I say? Bringing the show back was perhaps the single worst idea in Fox TV's history.
I'd have agreed with you on the Simpsons back in 2004, but I think the seasons following the movie have had a step up in quality. Definitely better than seasons 11-14. Season 15 was actually quite a strong season: "The President Wore Pearls", "Today, I am a Clown", "'Tis the Fifteenth Season", "I, D'oh-Bot", "The Ziff Who Came to Dinner", "Simple Simpson", "The Way We Weren't" and "Fraudcast News" were all good episodes. They ditched most of the over the top goofiness of seasons 11-14 and went back to focusing on secondary characters and more normal events.
Seasons 16 and 17 were quite bad, with only a few good episodes each ("My Fair Laddy" was great). Season 18 wasn't great either, but it did feature "Springfield Up" and "24 Minutes", two great format benders. Season 19 was filled with a number of good episodes. This season followed the movie, and I think this helped as since the movie brought in a lot of great old talent from the classic days, the current team learned a few things and cranked out some great episodes. "Husbands and Knives", "Funeral for a Fiend", "The Debarted", "Dial 'N' for Nerder", "Mona Leaves-a" and "All About Lisa" were good episodes. But the crowning achievement of season 19, the best episode of the post-classic era and one of my top ten favorite Simpsons episodes of all time was "Eternal Moonshine of the Simpson Mind". Such a great episode. It almost acts as a series finale. If focuses on the series as a whole, puts Homer's life at the forefront (from a baby to an adult), has a ton of trippy animation moments and ends with all the main characters throwing a party. Loved it.
Season 20, I'll admit, wasn't as strong but it did bring the series into lovely HD with some excellently animated episodes. "Take My Life, Please", "No Loan Again, Naturally", "Gone Maggie Gone" and "Coming to Homerica" were good eps. Best of the season was "Eeny Teeny Maya Moe". Again, one of the best post-classic era episodes.
This sort of trend has continued since, with all episodes looking great in HD, each season producing eight or so very good episodes and each season always brings about one or two great episodes. I really liked 21's "Treehouse of Horror XX" and "The Color Yellow", and really liked 22's "Flaming Moe", "Homer the Father", "The Great Simpsina" and "Homer Scissorhands".
Yeah, after SEGA (or as much as SEGA), I'm a huge Simpsons nerd.