I posted these a while back in the general forum but the post was quickly lost so i will post here as it's a much better place for the request.
I suggest the following new ept_types for the plugins GUI/Properties as i think these would help make the visual part much more organized, hopefully other developers here will like these suggestions also.
1) Paired/grouped values like you already have with the Common properties for Position and Size. It would be nice to have these available to use for regular plugin and behavior properties also. I have made a few plugins where i have many sets of X/Y values and each needs it's own item making the vertical size much longer than it needs to be so for me this would be very helpful.
2) A separator line. Each item is already separated by a thin line so maybe it could just make that line chosen color and also slightly thicker, maybe with a optional title text. This would be helpful if a plugin or behavior was slightly more advanced and you wanted to organize the properties into a few groups/sets.