Hi, could you make smaller size of Unreal editor installation and smaller projects size?
For example, let’s say maximum 3GB on HDD for editor + projects.
For, indie development, it would be extremely helpful to make Unreal compact.
Hi, I’m writing this with all developers in mind 
The first question, did you try customizing your installation already?
In launcher it’s possible to remove some platform-specific parts of the installation, templates and starter content. This way can remove a lot of content you’d never use
Decreasing size of core engine? It doesn’t matter. The basic installation eats 9 GB. Even if it’s possible to make it smaller, it won’t make a difference. I’d be against assigning any engineer to such task. 256GB SSD is a reasonable minimum for a game development and not that expensive anymore.
Next thing eating your SSD is project’s cache. It’s simply remain huge so editor wouldn’t have to crunch the raw data all the time.
This brings us to the second question: are you using Shared Data Cache already?
If you’re working on LAN with some people, I’d recommend configuring it, so the only one version of data cache will be stored on server. It accelerates teamwork and saves gigabytes on your local drive.
The last thing. If you’re using Git or SVN, simply stop. It creates local repository (a duplicate of your project + many versions of assets).
Consider using Perforce. It doesn’t create any local repository on client machine, so it doesn’t steal a precious space. And Perforce’s performance is still a way better than Git/SVN when it comes to binary assets.