Review structure

I've been adding microdata markup to some reviews recently, as well as
harvesting reviews from other sites, and have found that the current
reviewBody and ratingValue properties are often too coarse-grained to
properly describe the reviews.

For example, this review of a restaurant has 3 separate aggregate rating
values ("food", "decor" and "service"), but they're just marked as
"ratingValue" with no way to distinguish between them using the microdata
alone:
http://www.zagat.com/r/kevin-rathbun-steak-atlanta

Another example is this review of a film, which has three rating values
(not marked up as "reviewRating", in this case), each with its own section
heading and review text:
http://www.littlewhitelies.co.uk/theatrical-reviews/belle-26939

A third example is the peer reviews of this academic article, which contain
structure within the review bodies - "Basic reporting", "Experimental
design", and "Validity of the findings":
https://peerj.com/articles/435/reviews/

I'd like to be able to extract all that information without having to do
extra HTML parsing and analysis after reading the microdata.

One solution I can think of would be to add a "reviewSection" property,
having a "reviewSectionHeading",  "reviewBody" and "reviewRating", for each
section of the review. There may well be a better solution, though…

The AggregateRating class would probably need something similar (as in the
Zagat example above).

Does anyone know if this has been discussed anywhere previously, or whether
there are analogous "section" properties in classes other than Review?

Thanks,
Alf