Pattern IS Shallan's Shard Blade. Ivory is Jasnah'a Shard Blade.
Dalinar has visions of the Radiants where their armor glows as "if alive with stormlight". Their helmets disapear and reapear without being removed like current Shard Blades do.
It is an accepted fact that the Radiants betrayal killed a ton of Spren (per Syl and Pattern. I believe their are other sources.).
Syl describes the Shards weilded by non Spren bonded hunans as being "wrong".
Navani talks about how Shard Blades, like Shard Plate, didn't dissapear and reapear. It was only after trying to ornament the blade pomels that this was accidently discovered.
They haven't been able to discover how to even really come close to recreating Shards (with a minor success in half shard shields that don't regenerate once broken)
With all this, doesn't it serve that:
A ) Shard Plate and Shard Blades have a similar origin (probable)
B ) Given the above, if Pattern and Ivory are Shallan and Jasnahs Shard Blade, They may also be able to manifest as Plate (the Radiants, as stated above, were able to dismiss their armor like Blades currently are.)
C ) Shard Blades and Plate are essentially the physical representation of the dead Spren which were killed when the Radiants broke their bond with their Spren. Literally, dead bodies of Spren.
D ) Spren aren't repulsed by Shards. They are repulsed by Shards scavenged when the Radiants broke their bonds with their Spren. They are repulsed by us using their dead Kins bodies. A living Shard like Pattern or Ivory isn't repulsive. They are alive and manifesting themselves.
