This is annoying, and I've been wondering and wondering why researching traits doesn't give anything towards progression in a craft?!
To me, the idea of researching represents your character taking the item apart, getting deep down into it, and learning something from it (the trait). Not only does it represent that, we lose the item (as we should), and have to wait anywhere from 6 hours (without the skill that decreases them), to 3 days maybe more as I'm not sure if the more traits in a given piece you research if additional traits take longer, or if certain traits just had some time frames applied.
I think the XP should be based on that research time...the longer the more you get as I would think that extra time means there is more involved 'work' being done to research the trait.
Please reconsider having researching give XP.