What EAV should really be called is "unscalable".
While having a table or two in your application that are in EAV format should be fine the programmers who try to build an entire application using 1 to 4 EAV tables holding all the application tables are a riot.
I do not know how many times over the last decade I have seen threads where the OP finally laid out the design of their application after trying to get help on a query. For some reason the developer thought that their was the first shop to ever try this idea. The developers were usually not happy when presented with links to articles on why the design will usually not work in the real world.
I have never heard of Open Schema for this.
-- Mark D Powell --