Human‑in‑the‑loop currently supports only a handful of options, and they’re not very universal. The idea itself is great, but to make it truly versatile it would be extremely beneficial if you could send HTTP requests and wait for a response. That way, messengers such as Mattermost (there are existing nodes, just not for Human‑in‑the‑loop) or custom‑built solutions could be supported more easily.
Implementing a “send, then wait for response via webhook” pattern would eliminate the need to string together multiple flows or stack several webhook triggers in a single flow. It would also make it much clearer which flows are still running and which are finished. With the current approach—two separate flows or triggers—you see only that one request was sent. Unless you rely on variables, it can be quite difficult to match the second execution (the response to the user input) to the first execution of the flow.