This dialog is pretty much correct I think. There's a difference between writing something abstract and writing something unidiomatic and needlessly difficult. Hiding behind supposed goals of abstraction and complexity to excuse bad writing is not an easily definable thing, but like pornography according to the Supreme Court, "you know it when you see it" if you are a relatively experienced composer.
My use of harp is very sparing, but that's roughly in line with how it should be used. As Thomas Goss (of OrchestrationOnline) says: decoration, filigree, support. The harp is like dessert, adding great delicacy to a thin texture but rapidly becoming stale if overused. Every orchestration challenge he issues stipulates NO HARP CONCERTOS for a reason: beginner composers see the double staff and get overexcited about what they (think they) can give the harpist, and wildly overestimate the instrument's real capabilities. At the end of the day the harpist has an ungodly difficult part that just gets drowned or forgotten in the texture.
Let the harp do what it does best. The harpist won't mind if they have to sit and count some rests any more than my poor trumpet players will. They're paid to do that, so to speak. Notice that some of the most idiomatic harp writing I employ comes in the come una danza sections where I use glissandi and rolled chords - two extremely common and standard harp techniques to just add some background lush flavor to the texture. The exact notes played, insofar as they make the right chords, aren't important. The most I have the harpist do in a foreground role throughout the entire piece is that little dainty rising scale in the reprise of the danza. Again, decoration, filigree, support.
To the other point, this work is actually not drawing on minimalism at all. The glacial note values are an emotional expression tool, not an attempt to simplify or pare anything down. My contrapuntal lines are actually fairly intricate a lot of the time even when the note values are long and the textures are thin.