The spring boot dread: which of the defaults are a terrible idea to replace, and which of the defaults are a terrible idea to keep?

I do wonder, when looking at the examples, if it might be nice to have a spark/javalin-like that depends on okhttp and reuses everything that appears on both sides of the connection. okhttpd if you like, even if perhaps still best built on top of jetty, like spark/javalin. Might have some skill reuse benefits, but might also cause some unintended shortcut accidents when the type system can't tell upstream from downstream objects.