Hindsight's always going to be 20/20, so it's easier to go back now and assess their careers. Like others, I think most of U2's material soars live. That doesn't make their studio-recorded counterparts shit by comparison, just different, that's all. All of what follows is personal preference, not the definitive word on everything, please keep that in mind:
Boy
There's not much I'd change here. Maybe add "11 O'Clock Tick Tock" in there somewhere, but it's as solid of a debut as you'll ever find from any band. This is easily my most anticipated remaster of the 3 about to be released.
October
I've always had a soft spot for this album. Sure, it's not what it could've been due to the missing lyrics and seemingly rushed recording process, but they just wanted to get a new album out to retain interest. That being said, I don't know what to add here, but I would get rid of "Is That All?" ("The Cry" in disguise) and re-arrange the order a bit.
War
Again, not much I'd add here either. Cut out "Red Light" and maybe "The Refugee" (to me, it always sounded more akin to something like "The Cry" and would work better as an intro to another rocking song, like "Like a Song..." for instance). I'd also use the extended version of "Seconds" here. Switch "A Celebration" with "Two Hearts Beat as One" and make the latter a one-off single. Production-wise, there's not much I'd improve here.
The Unforgettable Fire
As it stands now, it's one of my favorite U2 albums, but like others have said, I wish a few more tracks could've been included (Three Sunrises, Love Comes Tumbling, Boomerang II, Bass Trap). I'd swap out "4th of July" in favor of "Bass Trap," actually. I wouldn't fix a thing production-wise, a remaster would really help this though. Here's how I'd have arranged the tracks though:
1. Bass Trap
2. The Three Sunrises
3. Pride
4. Wire
5. Indian Summer Sky
6. Boomerang II
7. The Unforgettable Fire
8. MLK
9. Bad
10. Promenade
11. Love Comes Tumbling
12. Elvis Presley and America
13. A Sort of Homecoming
The Joshua Tree
My 2nd-favorite U2 album after Achtung Baby - I wouldn't change much about this album, except cut "Trip Through Your Wires" in favor of one of the awesome bonus tracks that came out recently. This tracklisting here is for shits-and-giggles, basically what I'd like if this came out as a double album as originally planned:
Luminous Times
1. Beautiful Ghost
2. Where the Streets Have No Name
3. In God's Country
4. Spanish Eyes
5. Rise Up
6. Desert of Our Love
7. I Still Haven't Found...
8. Red Hill Mining Town
9. Bullet the Blue Sky
10. Silver and Gold
11. Deep in the Heart
12. With or Without You
13. Luminous Times (Hold onto Love)
14. Running to Stand Still
15. Race Against Time
16. One Tree Hill
17. Exit
18. Mothers of the Disappeared
Rattle and Hum
Ugh. I'd have released the studio and live cuts separately or on different discs of the double album, not mixed together. Throw in some of the b-sides like "Everlasting Love" and "Dancing Barefoot" with the other studio material and you're solid.
Achtung Baby
My favorite U2 album by a country mile - the only thing I'd change here is production-related. I wish the guitars were brought up a little in the mix, the acoustic guitar was added to "Wild Horses," and a couple of the songs were made a bit louder ("Love is Blindness", "Wild Horses", and "Tryin' to Throw..."). To me, it's the closest they've gotten to making a perfect album.
Zooropa
Like The U.S.S Excelsior, this was a great experiment. I'd cut "Babyface" and "Some Days...", re-record "Dirty Day" (In its place, I'll use the Bitter Kiss Mix) and fix the order a bit. I always end up listening to it and the Passengers album together anyway, so I put together a combo mix for my own amusement:
Always Forever Now
1. Zooropa
2. Slug
3. Miss Sarajevo
4. Stay (Faraway, So Close!)
5. Always Forever Now
6. Daddy's Gonna Pay for Your Crashed Car
7. Numb
8. Dirty Day (Bitter Kiss Mix)
9. Lemon
10. Your Blue Room
11. The First Time
12. The Wanderer
Passengers
The songs I didn't use above would be released as an EP to hold off before the new album comes out. "Elvis Ate America" and "Ito Okashi" would not make it though, mainly because they suck.
Pop
All things considered, this is still a pretty cool album. Sure, it needed another month or two to gestate and most, if not all, of the songs were superior live, per usual, but it's still a good listen. I'd add "Hold Me, Thrill Me, Kiss Me, Kill Me" and "North and South of the River", while "Wake Up Dead Man" is a good song, it's not really my cup of tea, that's why I don't include it. "Miami" is a nifty b-side at best:
Godzilla (one of the running titles of the album before they settled on Pop, I've always dug this title so yeah, here you go)
1. Mofo
2. Discotheque
3. Gone
4. Do You Feel Loved
5. The Playboy Mansion
6. If You Wear That Velvet Dress
7. Last Night on Earth
8. Hold Me, Thrill Me, Kiss Me, Kill Me
9. Staring at the Sun
10. If God Will Send His Angels (Single)
11. North and South of the River
12. Please (Single)
All That You Can't Leave Behind
It's a pop-oriented album, but still has a pair of "future classic" tracks ("Beautiful Day", "Walk On") to stand against their previous classics. I've always dug the laid back, R&B-influenced production here, and the use of samples in "In a Little While." Songs like "Wild Honey" and "Grace" are nice b-side material, but not fit for an album, methinks; "Elevation" would best be served as a soundtrack song or stand-alone single, not in the context of the album. "Peace on Earth" would've been best as a pre-cursor to "Walk On," like the live performances. The original album is too single-heavy toward the top - the following mix puts the more light and acoustic songs toward the top (including "Sweetest Thing," which would've never been released before until now) while the second half concentrates on the ballads and Million Dollar Hotel tracks. "The Hands That Built America" takes the place of "New York" as the requisite song about America/NY, while being slightly more subtle about it:
Wild in My Heart (still iffy on the title, but it fits for now.)
1. Beautiful Day
2. In a Little While
3. Sweetest Thing (Single)
4. Summer Rain
5. Flower Child
6. Stuck in a Moment (Acoustic)
7. Kite
8. When I Look at the World
9. Stateless
10. The Ground Beneath Her Feet
11. The Hands That Built America (The Edit + 2.5 VariSpeed)
12. Peace on Earth / Walk On
Maybe the songs that were cut here could re-appear on a U2:7-esque EP.
How to Dismantle an Atomic Bomb
Not only were most of the tracks over-produced (too long of a gestation period compared to Pop's short time), but they're all incredibly loud. The dynamic sound is lost and there's not much difference between the quietest and loudest moment of a song, which really bites. Other than production changes, I'd cut "Yahweh" and make the first verse and chorus "One Step Closer" the outro to "Sometimes..." (like the "Shine Like Stars" verse of "With or Without You", for instance). I'd include "Electrical Storm", "Fast Cars", "Smile", and "Mercy" to bulk up the album. This is still a singles-oriented album, more so than ATYCLB, which comes across as more complete by comparison, but it's making some chicken salad out of semi-chicken shit, at least by U2 standards:
One Step Closer
1. City of Blinding Lights
2. Vertigo
3. Crumbs from Your Table
4. Miracle Drug
5. Smile
6. Sometimes You Can't Make It on Your Own / One Step Closer
7. Love and Peace or Else
8. All Because of You (Alt. Version)
9. Fast Cars
10. A Man and a Woman
11. Original of the Species (Single)
12. Electrical Storm (William Orbit Mix)
13. Mercy
Phew, what do you guys think?