The mediawiki engine was programmed in the PHP language because of historical reasons. PHP is more advanced than outdated perl scripts but it has major performance problems. The question is which programming language fits more to modern needs? One idea is to use king of programming languages which is C++. C++ is the fastest language available which is supported by independent compilers. It can be used for creating web-applications and outperforms PHP easily. Another alternative is Python which is an easy to use beginner language.
Some wiki systems were written in the C++ language already but they are not used in reality. And python as a language is much slower than PHP. A possible third candidate is https://en.wikipedia.org/wiki/Wiki.js which is working with node.js in the background. In contrast to C++ the Javascript language is accepted widely for web-development. IT's only bottleneck is, that it doesn't provide object oriented features so it can't be used for building larger applications. But is this assumption correct from todays standpoint?
https://www.geeksforgeeks.org/prototype-in-javascript/ describes how to create prototypes in Javascript which are lighter object oriented templates. Recent versions of Javascript are equipped with full blown oop features including inheritance. So it make sense to take a closer look into the WIki-js rendering engine. The advantage is, that the GUI which is shown in the webbrowser and the backend application is written in the same programming language. This provides – in theory – more better user experience than the outdated mediawiki engine written in PHP.
An online demo for “wiki.js” isn't available. What goes into the direction is the visual editor of Wikipedia which is based on node.js. The normal mediawiki backend system was realized in PHP. It seems, that the developers are happy with this idea. One reason is, that PHP was designed as a backend language, while javascript is famous of it's ability to embedded textboxes and forms into the code.