Hi Stiophan,
Always great to see some more tectonics work here! I always wonder if there shouldn't be some sort of separate forum for those of us doing this ground-up stuff from tectonics onward, although perhaps it's not necessary as not many are crazy enough to try!
Overall this looks mostly fine, and your plate boundaries look good when I look at them on a globe which is always a plus. If I have one general critique it's that the subduction zones appear to be quite far removed from the continental shelf in general, when in reality they tend to be located close to the edge of continents, where oceanic crust plunges beneath continental crust (the main exception on Earth is the southwestern margin of the Pacific Plate, where New Zealand, Fiji, and the New Hebrides all rifted off of Australia relatively recently). Some examples of this include the southeastern margin of your Koryyn'a Plate, the northern margin of the Qashqavand Plate, and most of the subductive margin of the Marazaeth Plate. For many of those I'd recommend having at least some microcontinents closer to the plate boundary (think New Zealand or New Guinea), or moving the plate boundary closer to the continent.
Another thing that seems iffy is the several examples of triple junctions that have a rift meeting a subduction zone. At least on Earth this doesn't seem to happen often, especially not in the middle of the ocean. I suspect that it's not really a stable boundary, as weird things happen when a mid-continent ridge is subducted. Annoyingly enough this boundary tends to pop up quite frequently when you're working on your tectonic history in GPlates (as I suspect you are), and I'm in the middle of re-doing my tectonics partly to get rid of this. I suspect that part of this is that plate boundaries tend to shift more than we think they do so it's necessary to continually update your margins to reflect this. Of course this isn't necessary and I think everything here is technically possible, so feel free to ignore any of this!