I think also the thing about hip hop and sampling resulted in a series of attempts to incorporate one particular musical genre into hip hop, like jazz, country, classic rock, etc. But given the financial issues involved in pop music, it's most productive to pay for one really identifiable sample from a previous top 40 hit. I don't hear as much creative sampling as a whole I'd say with the rise of hip hop. The way I see it, sampling pop tunes will unsurprisingly tend to make a track more popular, but pop has such limited musical content that it tends to drag down hip hop, I think.
I also liked the hip hop-jazz era, I think partly because jazz samples are inherently musical: varying dynamics and instrumentation, complex chord structures and modulations, etc.
But I'm not sure trying to look to a single musical genre for inspiration and sounds is going to be very productive anymore. Overall, I think hip hop needs more composition. The most engaging tracks to me are those in which there tends to be more going on in the track, with more interaction between the vocal and the music. A lot of tracks are probably developed by some people putting together two eight bar loops in some configuration and setting it up to be rapped over by the named artist. That's a very limited compositional process that is going to yield very limited results. An alternative example would be the Beastie Boys, who had every reason not be accepted as serious hip hop artists but who managed to break through almost entirely through good composition, IMO.
About fifteen years ago a fiiend commented to me that what he liked about rap was that the essential message was, my dick is bigger than yours. I kind of miss that sentiment in today's hip hop. I'd like to see everyone get over the "If you step on me I'm going to bust a cap in your ass" thing and get back to the basics, like "If you step on me I'm going to sleep with your woman, and she'll like it." But maybe that's just me being sentimental.
peace