There's all this talk about "experimental" U2 in some albums, but sorry, I don't see it. U2 is a rock band and have always worked within that genre. Every time we say "experimental" it's not - it's just a slightly different sound for U2.
U2 deviated from their past sounds with UF, "Zooropa", and a few token tracks on "Pop", AB and HTDAAB (yes, the new album). But to stay it's "experimental" is questionable.
"Pop" is not this highly experimental album so many claim. It has two more techno sounding songs with "Do You Feel Loved" and "Mofo" and one more "unique" song with "Miami". All the rest is traditional U2 - either rocking ("Discotheque") or classic sounding ("If God Will Send..." and "Staring at the Sun").
AB is also not highly experimental - just a different style for U2. Yes, it incorporates more beats and grooves, but is that "experimental"? Furthermore, AB also has traditional U2 ("One") and rocking songs ("Until the End..."). What makes it stand out a lot more than it should is the shift in this sound from JT. But really, this is a pretty straight-forward rock album with faster beats than JT. To my ears, it's not a radical departure in sound (and one that could be heard in songs like "Exit" and "God Part II").
UF experimented because it contained instrumental tracks ("4th of July"), songs written on the spot ("Elvis Presley..."), songs with no guitars at all ("MLK") and songs built almost entirely around 2 notes ("Bad"). Still, it also contained plenty of rock songs.
HTDAAB is mostly a straight-forward rock record, like AB. However, there is some deviation with "Fast Cars" and "Love & Peace...". These two songs are like nothing U2 have ever done, but still are "rock songs".
"Zooropa" has a few songs that are far more experimental, but they aren't all that good ("Babyface" and "Some Days..."). And some songs are in the vein of AB ("Zooropa") while others just have a guest singer but are still classic U2 ("The Wanderer").
In other words, if we must say "experiment", then U2 experiments within the very finite boundaries of the rock music genre. They examine different beats, rhythms and sounds. They visit their past repeatedly, but make it fresh. They try hard not to repeat messages or ideas.
The only time U2 were truly experimental was with OS1, and they didn't even release that under their name!
Bottom line: if HTDAAB isn't to your liking, cool. Just don't say it's not "experimental" enough, because that term isn't applicable to most U2.