I've been trying to figure out for some time now why some fans really don't like the song Burn This Disco Out, and there's 3 main reasons I'm conceptualizing: 1. The song's placement on the album 2. It is not as easy as other songs on the album to sing along to 3. Unconventional chord and beat progressions.
First, let's address reason 1. BTDO is a party-themed funk/dazz song that is last on the track listing of an album that already has a few of those. It is a great closing song by itself (imo), but it is lyrically and thematically too similar to songs such as Get On The Floor, which I would enthusiastically agree is superior.
2. BTDO is sung in a interesting way where there is a "rise" and then a "fall" in the first line of each verse ("There's a stam-(rise) pede (fall)" / "You can take (rise) it (fall)"). Of course Michael emphasises it by singing with the dramatic style he always brought, but imo it makes it harder to follow even when sung in a lower register, as most do when singing his earlier stuff.
The choruses, which are usually the easiest part to follow along, are also a little unusual. The combo of progression + the way Michael's backing vocals on it are layered means you can't actually sing all of it at once. The dragged out "sit us dowwnnnn" is interrupted by a much faster "gonna dance, gonna shout, gonna burn this disco out". And then the post-chorus gets even more difficult with a very high, airy "groove all night" sung in falsetto that is paired with lyrics sung in a much lower tone. It's like a tapestry of clashing colors being woven together to make one interesting piece.
Lastly, 3. the chord progression overall. As mentioned before, it is unconventional and falls on uneven counts in many parts of the song including the chorus. But it is most strikingly unusual at the very end when the chorus repeats. This is where I wish I remembered anything about the names of keys, notes and chords, because I would put them here and it is really hard to explain otherwise. The chords of the bass fall, rise, fall and rise again on an uneven 3-3-2 count repeatedly and are paired with high, climbing horns in a way that would make it difficult if you just wanted to hum along to the music. When I first heard this song the progression of the end is what stuck with me the most, in a way that was almost confusing but exhilarating, and I can definitely see why it would be middling.
All of that being said, I of course still think this is a really great song, not just as a closer but by itself as well. There's a lot going for it in the usual Off The Wall formula: great instrumentation (i ESPECIALLY like how the rhythm guitars are layered throughout, and how the trumpets and horns compliment Michael's voice), well-mixed, and Michael's vocals are strong, bouncy and fun. It takes a skilled vocalist to not only layer over himself as a main and background singer but to hit the highs and lows that even other skilled singers would have trouble replicating.
The last thing I'll add on to this post is a fanmade extended mix that utilizes the multitracks of the original song and, aside from the annoying sound effects in the beginning, helped me appreciate and engage with the song more when this remix first came out.