I don't really think about the lyrical/thematic concerns of hip hop or how they might be limiting any more. I kinda remember vaguely wishing it wasn't all post-gangsta but that was when I was just starting to get into it, the same way I thought house was "too repetitive" when I was first getting into it.
Thing is, saying something like "house is too repetitive" is simultaneously sensible and non-sensical:
sensible insofar as the speaker might like another, less repetitive style more
but nonsensical insofar as repetition is the <i>point</i> of house: a lot of the enjoyment comes from seeing how the music works within those constraints.
And US hip hop - which, as stelfox says is actually astonishingly varied anyway - is kinda similar to that. The deliberate repetition of certain topics and themes becomes a frame for developing and showing off other things - a distinctive voice, great wordplay etc. And then there's grooves, sonics etc.
Guns and drugs and booty may seem like odd, arbitrary choices for frames but, well, afrofuturism doesn't seem to work any better. Probably any topic would become boring if elevated to the same level of predominance - that's the price of focus.