(Just go over to https://blazor.net/community.html, pick a demo and fire up your web inspector of choice)
For this to be practical, it needs a lot of trimming down, and I'm not sure how viable it is to do AOT and go through all the assemblies to do branch pruning before generating a cut-down WASM.
I do see a lot of appeal for enterprise scenarios and code reuse, and I guess there is a lot of potential there.