I think that one tone that can't be ignored is the reminiscent tone. The speaker is somebody that lives in the poem's town, and is somebody that used to watch Flick Webb play high school basketball. Several of the poem's stanza are the narrator's reminiscences about how great a basketball player Flick was.
However, I don't think that "reminiscent" quite captures the main tone of the poem though, and that's because reminiscent is a fairly emotion-neutral word. I can be reminiscent about all kinds of different things, and I will have a different attitude about many of them. I might be happy, sad, or remorseful for example.
I think the speaker's main attitude regarding Flick Webb is a mixture of remorse and sympathy. That tone I really get from the final stanza.
Flick seldom says a word to Mae, just nods
Beyond her face toward bright applauding tiers
Of Necco Wafers, Nibs, and Juju Beads.
Those three lines are so sad. I can't help but feel some sympathy toward Flick's situation. He was so great at something, but now he just quietly stares at candy racks and imagines better things. That's sad.
I also really feel the remorseful tone from the speaker during the fourth stanza.
He never learned a trade, he just sells gas,
Checks oil, and changes flats. Once in a while,
As a gag, he dribbles an inner tube,
The lines are similar to the final lines. It's clear that Flick wishes for the good old days of playing basketball. But it's also clear that Flick lived so much in the moment of his basketball greatness that it hurt his future. He never focused on anything that might happen after basketball, and now he just pumps gas. It's a regrettable situation that makes the reader feel the speaker's remorse.