I have never used my exile like that, but I often use the Handmaiden in a similar way. So basically an unarmed guardian with armor, just no weapons. I will certainly be a challange in certain areas but based on how well Handmaiden does unarmed I think it could be done.
Scion could be somewhat of a problem, but, Kreia is easy to beat as a guardian IMO. This sounds like an intersting build. What would be awesome is if you could use pressure point defence while unarmed, so you could stun your opponents...maybe a mod...pressure point gloves or something...
Viva La Resistance!