Unfortunately, dontdamnmeuyi2015 is correct, nothing they come up with would sound like the old days...
But, damn it, they should know by now that the only way to produce some seriously cool and heartfelt shit is to be a BAND again, even if just for the preproduction and recording...they should "lock" themselves in a mansion or something (remember making of Blood, Sugar, Sex, Magik by RHCP) for a few weeks and write off of each other, like a fuckin' r'n'r band should be doing, not some copy-paste nonsense. And build the songs the way they used to, with those mentioned bridges and codas that we all love...I don't know if it is an Izzy thing or what, but with Izzy in the equation it would be pretty close to the "organic" classic GN'R sound...wishfull thinking I'm afraid. Just "lose" a month of your life, put aside your comfort zones and give us and yourselves one last bitchin' GN'R record!