To be fair, I should probably have said evolved junk rig.
After all, on Earth, the primary user of the junk rig was China, whose uses for it were (a) primarily mercantile, and (b) primarily fluvial and littoral. A few abortive experiments such as Cheng Ho’s expeditions aside, it was a land empire, not inclined to naval power.
Alatia, by contrast, was very much a naval power, so you have to think on what the junk rig might have become if the British Royal Navy had turned their collective naval architects on to relentlessly improving its performance. 
Such evidence as we have from modern experimenters with modified junk rigs seem to bear out the possibility of this, incidentally - specifically, that battens able to flex and/or be independently sheeted and create shape in the junk sail increase both speed and ability to sail close-hauled, as do intentionally cambered junk sails vis-a-vis the original flat-sailed rigs, to the point where they can outperform current Bermuda rigs in these areas.
Unfortunately, all the evidence I’ve found comes from small sailboats as no-one’s building tall ships quite that experimental these days, but I think the extrapolation is valid enough for fictional work.