Two dialects: ShEx with a SPARQL/SPIN-friendly subset?

It seems like there are two major camps in the RDF Shapes WG: (a) those 
who want a SPARQL/SPIN-friendly language; and (b) those who want a more 
expressive and concise language like ShEx.  Has the WG considered 
standardizing a language with two standard dialects, such as was done 
with OWL?

It seems to me that if there is a significant number of people who would 
(continue to) use ShEx -- either because of its additional expressivity 
or its conciseness -- even if the Shapes WG decided to standardize a 
more limited and verbose SPARQL/SPIN-like language, then that is clear 
evidence that a ShEx-like language *should* be standardized, perhaps in 
*addition* to standardizing a SPARQL/SPIN-friendly subset of ShEx, as a 
standard dialect.

David Booth