You cannot escape the politics of browsers by going to WebAssembly, because that's where WebAssembly was born. To use features outside of the original WASM spec, you have to consult a table and perhaps use a polyfill, like with CSS or JS features. Browser implementers have a large influence on the direction of the VM. For example, around a year into the original spec's development, it switched from being based on an abstract syntax tree to being based on a stack in a decision made by the browser teams [1]. A big change like that, a year in! The s-expressions in the text format are an artifact of that period, since tools already relied on their existence for optimization.
Anyone who writes a compiler or engine for WebAssembly is going to have to deal with the mess of web standards, unfortunately.
1. https://github.com/WebAssembly/design/issues/755