Gaga could have sang some Adele songs. She totally wouldn't have been as successful, but it wouldn't have been as awkward as it sounds. She couldn't have done He Won't Go or Take It All or Lovesong, but everything else would've sounded good. Obviously she can't match Adele's tone on SLY or Set Fire To The Rain but it still would've sounded great.
I would be here for it, at least.