I'm not expecting anything but suckage from this ill-advised union, so I suppose there's always the chance of being pleasantly surprised. I assumed it was pretty much over after Malcom departed. As for Axl, I dislike his voice, and never thought much of GnR after about 1988 when I briefly found them a welcome slightly-gritty respite from several years of boring hair metal on the radio and MTV. But maybe it'll work.
As for AC/DC, I've never worshipped them, but I do enjoy their classic stuff, and I like that they have proudly stuck to the same formula with mostly solid results. Usually I like a band to take chances with their music and risk failure, but why would you want that from AC/DC? It's not what they are
I've found in my band that AC/DC songs are some of the most difficult to cover that we've tried. There's nothing to hide behind. With something that simple, you have to get the feel right, and either you convincingly bring the ROCK, or you don't. Technique isn't that important here, and you can't compensate by overplaying or embellishing either, it doesn't add anything good to that music.