Hi, Bartek from the Deno team here. We are actively looking into improving this situation and from initial investigations we were able to shave off roughly 40% of the baseline size, with more improvements possible in the future. Stay tuned for upcoming releases.
Tuned I am, happy to hear this is getting attention. Improvements in this domain would also enable Deno to be a more serious contender in the App space opened up via https://github.com/webui-dev/deno-webui and others.