> Several of the axes mentioned (memory management, language specialization) lack any documented attempts to systematize their treatment at the language level.

This is not entirely true. The author of the Gradual Memory Management paper you cite is currently building [1] a systems programming language called Cone [2] that incorporates these mechanisms. Although much work remains to be done, the online reference documentation does go into some detail about the syntax and semantics for references, allocators and permissions.

[1] http://github.com/jondgoodwin/cone [2] http://cone.jondgoodwin.com