Thank you for showing interest in Jouter. Your time and effort is much appreciated. Before you submit a pull request, please make sure your patches are in line with Jouter's development goals.
Please make sure tests are passing and cover all testable code. By testabe code we mean any code that does not touch HTML APIs on the global object.
Server-side features can only be added as a bonus. Patches that degrade the experience on the client-side will not be a good fit for Jouter, even if it makes life easier on the server-side.
Jouter takes semantic versioning seriously. Changes that are backwards-incompatible will need to wait until the next major release which can take a while.
Jouter is supposed to be light. As in really light. 1KB is an arbitrary number, for sure, but the idea is to keep it small. If your patch is going to double the library's size, you may be looking for a plugin system or something along those lines.
For the most part Jouter's user should not need to think about how Jouter works internally. Changes to the API that would introduce this kind of cognitive overhead are not a good fit for Jouter.
Each of the three placeholder sequences are carefully picked to cover some of the more common real-life use cases, and regex is offered for everything else. Unless there is a very good reason, new language for defining routes will not be added.