I'm not sure I follow. Phoenix is also MVC and its request model is far simpler than Rails'. In Rails we have controllers, we have callbacks (or "filters" as they are called now), and we have "middleware". That's three concepts right there! In Phoenix, we have a connection struct that flows through a pipeline of "plugs". Plugs are just functions that transform said connection. Each part of the request pipeline is implemented as a plug. You can create your own plugs and "plug" them in where you see fit. Read more here: https://hexdocs.pm/phoenix/plug.html

Of course, LiveView isn't MVC in the classic sense, but it still uses plugs. Its goal is to simplify the SPA which I'd say it does a particular good job of.

[Edited to fix part of a sentence I deleted by accident]