"Since TriG is standardized and thus cannot change,” well there can be friendly amendments proposed if they made a mistake but if there is data out there that actually uses tha feature then that would not work.
Apart from the bnodes scope its, the question of: @webr3 how to serialize TriG to N3? …. in other words how would you dump and load a quadstore using N3? We have to pick a predicate to use betweeen the id of the document (which they call named graph) and the graph. Before we have used log:semantics for that relation.
I had a go at some code to dump the store in fact.