I do think she could still put on a great show if she experiments complex, glamourous and evocative theatrics to create strong performances, spectacular and charismatic as they used to be, with a lower dance effort. Iconic and Heartbreak City from the RHT and Frozen or Extreme Occident from MX are good examples. Another huge possibility, left out for a very long time now, is to enhance the musical impact of her songs, realizing more creative and explorative arrangements that valorize the live instrumentation and vocal sound (the best example for that is the Girlie Show imo). The Dark Ballet rendition at Harlem, with Jon Batiste, was fire for me.
She has a lot of tracks that can still be performed live with a huge potential, like Frozen, Like a Prayer, Rain, La isla bonita, Rebel Heart, Borderline, Live to Tell and I could go on. The point is chosing a set list where the "get into the groove" M gets the stage for two or three tracks (stuff like Holiday, Music, Hung up) - wich would also be good in terms of silly costumes risk - and releasing some good new tunes that propose a more mature and experimental sound. So imo she could still put on an excellent show, absolutely, but she doesn't seem to be going that way, that's all.