I'd agree that Axl definitely brought the "ambitious, beautiful" element to Gn'R, but whose to say these guys can't create something like that together? Or what Scott can pull out of himself after going through all the shit that he has.
So far, I'd say Slither does lack that, and Set Me Free only glimpses at it, but if that other review is correct, and Slither is nearly the weakest track, then I think we're in for something great.
Axl isn't the only person that's ambitious, and everyone changes over time. Maybe Slash has grown up a little too.