This is definitely a loss. It's real, it's unfortunate. But the binary-vs-text change is actually pretty minor: a well-crafted binary protocol permits simple tools that can be used to debug it.
The actual problem here is that HTTP/2 is highly stateful. Connection state, stream state, and header compression state are all required to actually reliably debug a HTTP/2 flow. In practice, that means either your HTTP/2 implementation needs to be able to dump its state, or you need to capture the entire session to understand it.
For my part, I will not mourn the ability to telnet to a port and type HTTP. In practice, that approach lacks value in most modern cases. However, I will mourn the loss of tcpdump as a single HTTP debugging tool. Your implementations now need to make debugging possible in their own right.