I'm wondering if it would be possible for Radiants to power the Shardplate themselves. After all, the primary purpose of the gems (at least this is how I read it) is to provide Stormlight for the Plate. Theoretically, this is why Szeth's surgebinding interferes with it. He pulls the Stormlight out of the gems and the Shardplate has no power source.
If he were to consciously feed Stormlight into the Plate at a slow rate, though, I can see that working. Maybe that's what was what the Radiants originally did, and the gems were just there for them to continue to renew their supply of Stormlight. Like batteries.
[ThreadNecro]
I think this this an excellent theory. I approve of this theory.
Also, I think the Honorblades are the Herald's uber-Shardblades. 9 of which are probably still stuck somewhere or other, and one of which was last seen lying next to it's unconscious owner. (he ain't dead, cause Brandon sez he gets an expanded role later and he can't if he's dead. )
(edited to fix highly-unfortunate typo)