As developers are very particular and tend to customize their IDEs with a lot of extensions, I don't think this will replace the tools we have.
But I do think that we should be able to customize a lot more
The code editor especially should be able to receive most of the common settings such as font, theme, ...
I would also like to see some support for common utilities such as prettier and eslint. This will not replace the primary IDE but when I need to use it I expect it to do a proper job.