No, there has not been a consistent policy in dealing with equipped items. Equipped items are have mostly been randomised when they are notable and easily available, or when they are notable and/or some sort of replacement item can be arranged. Suryris' Blade is perhaps notable, but it is not easily available, and it's hard to arrange a replacement item without simply swapping it for a generic +1 halberd, so randomising it has not been a priority.
What do you mean with 'some sort of replacement'? Halberd +1 sounds fine to me and you can assign new location - there are still few unused out there (Doomsayer, ogre mages in BG, Revenant) ..
Anyway, its a awesome mod, good job
Anyway, its a fantastic mod