It's not a complaint, just a fact that gRPC has fantastic integration with very deep telemetry, and that anything off the beaten path (such as this alternate protocol) is probably going to require significant handholding/customization to make visible. Connect-web wont, out of the box, have any of this deep built-in customization, because it's right now a tiny player, and no one is going to do the work for you, unlike the couple big names.
It's ironic that you mention GraphQL. Yeah, to be honest, I find graphql to be barberic. Submitting all your requests to /graphql is a dirtbag piece of shit regression that only an idiot too stupid to remember how terrible & shitty SOAP was would ever have suggested. It'd offensively bad a premise, & it makes looking at HTTP basics like the path useless. But I use it at work & dont complain. It's well supported by most observability tools.
I have faith Connect-Web hasnt fucked up nearly as bad, but it's still not going to have anywhere near the sweet out of box L7 observability grpc nor graphql has and that's just obvious, uncontestable, clear, & it matters, a lot, & no protest or dislike of what Im saying alters that.
Graphql, in spite of it's dis-http piss-around attitude, is also the exact proof of how valuable popularity is; something connect-web protocol doesnt have now. I can search for specific graphql queries or mutations, or even specific arguments passed in to these queries/mutations- in nearly any major observability platform, in spite of this being fairly obfuscated data deep inside the http posted body envelope, because it's popular, because the work has been done to probe in.
You talk about respecting the features of new protocols. Im not trying to dis on Connect-Web- I have beef but it's elsewhere- but Connect-Web doesnt actually have new features. It's a new 3rd way to do what we already do. One that that will definitely clearly obviously uncontestably have less good tooling support than the we supported official protocol, & which exists only because the browser fucked shit up & failed to deliver, across 3/4 of a decade. It matters that the solutions we built around this shitshow are not as popular, not as supported, and while I like & respect connect-web protocol, I think it's necessary & truthful to view it as a relatively unsupported ideally-not-needed-at-all upstart; the very need for it is terrible versus just using the real, very well supported, highly observbable thing.
I genuinely dont get the objection. Being not-the-mainstream, being an alternate upstart alternative will almost certainly have less awesome support. That's a fact that needs to be faced, not smokescreened.