Take a look here: https://gdevelop-app.com/
It should have a cleaner & more modern look. Multiple pages so that future additions are easier (for example, there is already a new "education" page and a more complete "contribute" page too).
It's more focused on GDevelop 5 as I want to encourage new users to use it first
GDevelop 4 can still be downloaded here (or on GitHub), it's not removed.
The website should also be much faster (there is dynamic loading and aggressive pre-caching of pages), and responsive according to the screen size, always having a good look.
Let me know if you find obvious mistakes, errors or issues
Remember that you can help to translate the website on: https://crowdin.com/project/gdevelop-website
GDevelop lead developer