Gil Scott-Heron's work, especially "The Revolution Will Not Be Televised" was one of the vital connections between poetry and rap, and at the same time a reason some upcoming artists pushed forward with rap and not poetry. His birth in 1949 meant he was a little too young to become a part of that core group of black arts poets who were primarily born during the 1930s.
On the other hand, he was old enough to become viewed as "a godfather" of rap even though he was uncomfortable with that term. Whatever the case, I think the view of Gil Scott as a father-figure by rappers and rap fans (and even his abandonment of the role) is an integral feature of the music's history as well.
Gil Scott-Heron was clearly a lot of different things to a lot of different people.
Since I move in poetry and rap circles, I've noticed some interesting differences in how the groups, generally speaking memorialize him. Poetry folks tend to highlight the literary qualities of his work and appreciate his music as firmly rooted to a particular history.
Rap folks tend to memorialize Gil Scott as a crucial precursor if not originator of hip hop. The nature of the fiery, rap-like aspects of his delivery styles and content are pointed out more than his background as a literary artist.
Some of what we see with those differences are generational. Some are aesthetic.