Since it launched publicly on January 15th, 2001, Wikipedia hasn't had any major update to it's interface design.
There's nothing wrong with its current design - if it works, then don't fix it. However, if you're an Arc user, you should totally check out Wikiwand.
Wikiwand is an extension that drastically improves your Wikipedia’s reading experience by giving it a modern, clean look with tweaks like ability to listen to articles, change fonts, AI summarises and an option to read articles in dark mode.
Images are presented in a more prominent gallery format, making visual information more impactful and at the end of every article, it shows other articles related to your search subject to go deeper with your research.