in my opinion Pop doesn't need "finishing", and anything U2 hypothetically do to it in 2012 would only do more harm than good. They just need to live with the fact that the album was released as it was, warts and all.
I personally think it's one of the best albums they ever did, and completes a great trio of albums from the 1990s...but, and no-one here LIKES to say this, it seems like Paul McGuinness was right in the way he described the recording as being a case of 'too many cooks'. When you read about how dissatisfied U2 were with it, after reading how many people were involved in the bloody thing, it's no surprise they were recording/mixing at the very last minute. The songs are fantastic though and a lot of them stand up as some of their all-time best...
They tried re-arranging/remixing song for singles in 1997-1998, then a few remixes for The Best Of 90-00, and look how that ended up. Boom-Chas removed a start.
If they couldn't get it right in the first five years that followed the release of Pop, what makes them (or anyone else) think that U2 going into the studio
15 years later to 'finish' songs written by, let's face it, a very very different band, could possibly be a good idea. Just picture day one in the studio, 2012 Bono laying down a new vocal track for Mofo. It doesn't bear thinking about it.
If they insisted on redoing any Pop tracks, they should just remix what's already on tape. Not go in and add more to it. Strip stuff down, whatever...
Maybe even source vocals/guitar/whatever from live performances from Popmart. Would be very easy sync-wise, since a lot of the loop-heavy songs were obviously played to a click track, so you could get 97/98 Bono doing a proper job of singing Last Night On Earth and lay it over the original studio recordings. Or beef up Miami with the live rocking out. That way at least it's all from within the Popmart era and the U2 of the day and not a bunch of 50 year olds revisiting it and wrecking it. Hell, U2 could even get on with writing (shock horror) NEW material.