They added an async Channel and its actually pretty nice to work with, at least.

Agreed. This is how I feel using it: https://xkcd.com/297/. It's from 2012! I hadn't even written my first `public static void main(string[] args)` then.

My favorite parts of TPL Dataflow are using Channels + Encapsulate to create custom blocks, backpressure, and parallel execution while maintaining ordering. Great library. I sometimes wonder if it would be possible/useful to implement a TPL Dataflow 2.0 on top of Channels.