Recognizable base
Familiar route patterns still matter because they reduce entry friction.
There is no reward for making callers learn an ornamental route system before they can understand the surface. AIXE benefits from simple nouns and obvious baseline actions because those patterns already carry meaning for humans and many technical systems.
A clear base grammar lets the protocol spend its complexity budget where it counts.
Fast recognition
Callers can scan a route list and orient themselves without first learning a special dialect.
Stable surface
A conservative base grammar gives implementers a durable frame on which richer contract behavior can sit.