I don't think Atom wants to be a basic text editor in the first place. It's shipped as a basic editor but the killer feature is that you can easily hack togethe

I don't think Atom wants to be a basic text editor in the first place. It's shipped as a basic editor but the killer feature is that you can easily hack together extensions to suit your needs. It's a tradeoff: you pay for the html+js engine, but get a lot of potential developers. That being said, having worked with Atom on a larger project I can't confirm it's slow.