> you're truly writing web applications, which run entirely in the browser and only go to the server for data

I see this as a huge step backwards towards client/server. The web is a win because it's made of addressable, reusable semantic resources in open formats. Instead web apps ship data around in undocumented and unstable formats which are only understood by one ephemeral piece of code that you have to trust. If this really catches on it will wreck the web, leaving us only with the same pile of siloed apps we had in 1990 (but without the native code).