I use ASDF because it works and everyone uses it. But this monstrosity still makes me wince every time I see it, or worse, have to type it, or worse still, have to explain it and then feel compelled to apologize for it:
(asdf:operate 'asdf:load-op :some-package)
It's somehow emblematic of a larger (cultural, or something) issue too.
So a replacement for ASDF is probably a good idea, but it's the sort of thing that won't get off the ground before it's mature, and might have a hard time getting adopted even then. ASDF is just good enough, or rather just not bad enough.
Yes and no. There are cultural issues that cause Lispers to build not "a package system" but "a (complex) meta-system with which you can build your own package system", but I think there's still a recognition that the situation today is pretty lousy.
It sure seems like we've had ASDF forever, but it only dates to late-2002 -- before that, we had mk-defsystem (which was even worse). I think ASDF will turn out to be one of those things that people only used because we had no alternative. If XCVB is good, ASDF could die a very quick death.
So a replacement for ASDF is probably a good idea, but it's the sort of thing that won't get off the ground before it's mature, and might have a hard time getting adopted even then. ASDF is just good enough, or rather just not bad enough.
Edit: there are other attempts at this too, like http://mudballs.com.