Make no mistake SOE is a really good album for a band their age, a terrific effort all things considered (a top 5 U2 album in my book) but they used too many different, contrasting producers across too many tracks, instead of having (and sticking with!) a similarly aligned set of (2-3) producers across the entire album. (eg. Eno, Lanois, Flood partnership across the entirety of Achtung Baby)
I don't have an issue with over-production on SOE, only criticism is the production on the Blackout which completely neuters the track, this and Red Flag Day sounded neutered and could've benefited from a more raw sound and grittier production like stuff such as 'The Fly', 'Zoo Station'.
Songs like Landlady, Love Is Bigger, Lights Of Home are great songs in my opinion because of the bells and whistles, production effects, multiples layers of keys etc.. It brings a layer complexity and a modernity to the songs that simply isn't able to be expressed in a live setting with just the four lone band members. So in summary what I don't want to see is a stripped back U2 record, rather I'd like to see a U2 project in which they utilize the same produces throughout the entirety of an album (the same set of producers for each song) with an overarching theme/and soundscape that remains consistent throughout.
I'd love to see them stick to a certain sound and go for it. Landlady is a terrific song with a cool sonic soundscape/atmosphere which fits alongside Love Is All We Have Left, 13, Book Of Your Heart, Little Things, Landlady: they all fit the same general sort of sonic palette. Ideally SOE should've consisted of an entire collection of songs of that same general sound.
Clearly they aren't going to make 'Achtung Baby' or the likes again, that's unrealistic to expect from them at this stage of their career. However, they need someone who can say 'OK that need this here, that was terrible'. I think they've achieved what they can achieve with Eno.
Something more ambient, acoustic with synths (and less of an effort in attempting to write pop hits).. but just go all out weird with synths, theremin, xylophone, didgeridoo, mandolin.. whatever - experiment with completely different instruments that U2 haven't used before.
Fuck it, how about Kevin Shields from My Bloody Valentine (a guitar genius - listen to 'Loveless' and read how it was created if you are not familiar) to produce them and then Flood alongside Daniel Miller to get electronics back into it.
Perhaps just ditch the guitars altogether and go for some way out, effects driven songs, and some acoustic tracks, now that would be just perfect...