At least in some ways, it feels to me like Wireguard is more of a return to the "unix philosophy" (if there is such a thing) when compared to solutions like OpenVPN and ipsec/StrongSwan. Doug McIlroy, amongst the designers of Unix, said that tools should "Do One Thing And Do It Well." Wireguard seems like a great example: it offers very few knobs and levers in large part because the scope of its capabilities is very small. Wireguard manages the actual tunnel between endpoints, everything else (managing interfaces and routes, disseminating keys, autoconfiguring) is left for other tools. But, Wireguard provides a simple and friendly enough interface that it's easy to write other tools to do these tasks, ranging all the way from shell scripts to some big enterprise system.

This stands in clear contrast to OpenVPN, which attempts to manage all aspects of the VPN management process from endpoint config (interfaces, routes, etc) to key dissemination (strongly preferring mutual TLS auth and specifying a format for importable VPN configs). As a result, we could say that OpenVPN "Does Everything And Does It Okay," which I'd like to coin as the opposite philosophy. This has advantages if you have some kind of complicated situation and want to keep everything inside of one tool, but the result is that OpenVPN is more complicated to use and configure, and has more surface area to attack.

To some extent this kind of limited scope comes off as opinionated but I would like to view it the opposite way: Wireguard is unopinionated in that it leaves a large portion of the VPN stack for you to handle yourself, either manually or by bringing your own tool. This is a bit annoying if you're looking for a turnkey solution, but also makes Wireguard very simple and easy to understand and audit.