What are your expectations for the tour?
Assuming she will possibly tour again, what type of tour would you like?
Personally I would love the tour to be called Mayhem Ball as it is the concept Gaga has used over the span of her career. She can really make an album come to life on stage. I'm not as interested in a tour in which she performs her 'greatest hits', and I think she wouldn't want to do that herself either. She has worked hard on Mayhem so I would understand if that's the album which gets the main focus.
As for other songs, I feel like Born This Way would blend in really well with the Mayhem vibe. I'd love to see songs like Heavy Metal Lover, Government Hooker, Bloody Mary and Scheiße get added to the setlist. From other albums, Dance In The Dark, Replay and a few of the 'hits' (Bad Romance, Poker Face, Applause, Alejandro) would fit well.
She'd for sure do another acoustic set, which for sure would include Shallow and DWAS (although the latter would also fit as an encore). Maybe she could switch up the acoustic set every show. She now has quite a large selection of songs to choose from which she has performed acoustic before.
As for dates I can't really speak for it because I know how longer tours have affected her physical health in the past. The Chromatica Ball tour was shorter than her previous ones but it was manageable for her, so if that's what she wants to do I'm all for it.
The Joanne World Tour was announced 6 months prior to the first show, the Chromatica Ball Tour 4 months. She could kick off the tour in South America with the show in Rio (Madonna ended her Celebration tour with the Rio show) on May 3rd. This would mean, however, that ticket sales would have to start next month already which might be a bit optimistic. Alternative is to announce the tour after the Rio show instead of starting it, and then starting the tour around September.
What would you want to see?