Crush sounds more like Destination Anywhere than Undiscovered Soul IMO, but also when you think about it, alot of the songs written for Crush were by Jon intended for a follow-up solo album to Destination Anywhere. In early/mid 1998 Jon did a solo gig and played, at the time, new songs, some ofwhich made it onto Crush, Just Older being one of them. So it's quite an obvious explanation for why Crush is more like Da and hence why Crush turned out to be a more softer, poppier album.

And as for re-writing Livin' On A Prayer, It's My Life was I think written almost at the last minute of the album sessions, up untill then the working title for the album was Sex Sells.

I think I rambled a little!