Even with web apps, you can serve the same app from the same URI. URI doesn't imply static content.
Serving a slightly different web app from the same URI based upon other random metadata on the other hand. Makes caching all the more complicated.
Serving a slightly different web app from the same URI based upon other random metadata on the other hand. Makes caching all the more complicated.
I mostly think the replacement for user agent should be a boolean of mobile or not mobile. And everything else should be dynamically handled by the client.
The "garbage" we don't want to serve mobile, is often also garbage for desktop, autoplay videos, too many tracking scripts, etc. If we force people to optimize their site for mobile and desktop then maybe we'll actually get good desktop sites.
I agree tracking scripts and the like should be blocked and removed across the board. But I think there's probably a suitable amount of visible UI and content that should be shipped differently or less to phones, because of how they're interacted with.