Arguably sites have been increasing in size for one simple reason: It directly results in increased sales.
Everything is sales.
If cleaner, 'purer' sites made more money you bet the average web page would be 10kb.
It's all about what translates to more sales. As such, you won't ever see a return to more traditional websites. Look at Amazon with it's virtual dress models, heavy as hell, but they most certainly land more sales.
You know what I would really enjoy? Being able to sign into your Github account and sync your preferences and packages to the cloud. Then if I sign in on a different computer, all my hotkeys, packages and themes are copied over seamlessly.
But still, I would like this to be a core integration.
Agreed that this should be built in. I've been using https://github.com/atom-community/sync-settings which stores everything in a gist and has worked out reasonably well so far. The pain points are that you have to manually set it up the first time with the gist id and (optional) private api key, and backups have to be triggered manually.