U2 probably keep putting those on DVDs because they're their biggest hits. Its also possible that they might not put some of these (although Pride, Streets, and One are unlikely cast-offs because of their arrangement on this tour).
As to other songs - it's not totally impossible that Who's Gonna Ride Your Wild Horses doesn't make an appearence if they play it tomorrow. It will probably be All I Want is You on the DVD, though, since the video for that song was filmed in Milan...
Acrobat and Electrical Storm have never been played live (other than in soundcheck), so their chance of being included on any DVDs are none at this point.
I agree, however. If you look at the likely setlists for the Chicago and Milan DVDs, they're remarably similar:
On Both DVDs
Vertigo
The Electric Co.
Elevation
New Year's Day
Beautiful Day
City Of Blinding Lights
Miracle Drug
Sometimes You Can't Make It On Your Own
Love And Peace Or Else
Sunday Bloody Sunday
Bullet The Blue Sky
Pride (In The Name Of Love)
Where The Streets Have No Name
One
Zoo Station
The Fly
All Because Of You
Unique to Chicago:
An Cat Dubh
Into The Heart
Running To Stand Still
Mysterious Ways
Yahweh
Party Girl
40
Unique to Milan:
I Will Follow
I Still Haven't Found What I'm Looking For
All I Want Is You
Miss Sarajevo
With Or Without You
Original Of The Species
Keep in mind that this is just guesswork, but its still a bit disappointing compared to the distinctness of the two Elevation DVDs.
However, the sets lately seem to be a bit longer than in the past, so I can forgive more overlap.