I guess I have a wildly different interpretation of typical OLAP scenarios. To me this acronym mostly means "reporting". And in 99% of cases where the business desires a new report, the ideal views or type systems have not been anticipated. In these cases (most of them), I can't imagine a faster way to give the business an answer than just writing some sql.
SQL isn't wholly adequate for this, it's hard work to get the SQL right and if there's joins involved it's not hard to accidentally fan out and start double counting.
If you ask me, you want an analytic model of the data that is designed around measures, dimensions, with an anointed time dimension, and a way of expressing higher level queries such that it automatically aggregates depending on which dimensions you leave out, and gives you options to sort, pivot, filter etc. dynamically.
This doesn't look like entities, really, but it is a model between you and the SQL.
From my scan - not detailed - reading of the article, Moose looks too low level and not a useful abstraction to sit in the same logical place that ORMs do in OLTP databases.