Well, while EJ has his own thing going on, he's been quite up front about the inspiration behind the tones he goes for and specifically states Hendrix, Clapton and Richards, sometimes using a song as an example ("Start Me Up" was the one he used for his dirty rhythm). Satch has brought up "Machine Gun" many times over the years. Hahahaha and there's no way Joe Bonamossa(sp?) didn't put some effort into recreating EJ's lead tone!
I know in my experience, figuring out how to achieve someone else's tone has a lot of discovery along the way that I wouldn't have learned had I just focused on 'my own tone'. Since the majority of recorded tones on albums sound incredibly different solo'd than they do in a mix, a lot of that learning is figuring out how that ends up happening, which inevitably makes it easier to dial in your own tone.
Like the Edison thing and figuring out 3,000 ways to not make a light bulb; you're never going to completely replicate someone's tone, but in those 3,000 attempts, you'll gather a lot of information that helps you figure out how to make you're own light bulb. Or LED. Or frickin' lasers.