While I listen to Functional Geekery on the regular and do enjoy it, I would say Proctor has great guests but the interviewing style definitely has some room for improvement. The thing that comes to mind is explaining for every guest "and... I became aware of you through <some mundane details>" but there is a lot more to what makes me feel the interviews are a bit lacking in energy sometimes.
This one with Mathias Felleisen is an old interview from 2016 by the way, not sure why it's popping up here now.