Keep in mind that I'm just a user. I would like to think along in solutions, but at the same time, I really don't want to inspire false hope by doing so. The post below is just sharing my current thoughts on the subject.
If internet support would be included in FUZE, personally I'd prefer it if it would be an implementation that supports multiplayer games. If that is the case, the communication is always between the same game on different devices, so there would be no need for an URL. FUZE would need to do the heavy lifting for the implementation in this scenario.
If there would be support for communication with a custom end point (URL outside of the FUZE environment), then I still see many ways that could be used for unforeseen use cases if the host and/or port of the url can be dynamically modified. Considering that the Switch doesn't have a web browser, I suspect that would be a concern.
The best way around this that I can see, is that there would be an approval system much like for code. Where you can submit the URL of an endpoint, with a description on how it can be used. Where you agree that your internet traffic is monitored so it can be checked if the end point is used as described. That submission would then get an ID (just like your game would get an ID) and you would be able to use that ID within your code. Then as long as the submission is approved, it would be possible to use that endpoint within your code.
I don't see much use in limiting the body size that tightly, since offensive words tend to be short enough to fit. Limiting the body size mostly limits how it can be used for good, but less so how it could be used for bad...
