So, my understanding of things is that, as a result of the Recreance, the spren took the form of Shardblades because the Nahel bond was an attempt by the spren to recreate the Heralds; since the Heralds had the Honorblades, that meant the Spren's 'default' form would be Shardblades.
And we kind of see that play out when, upon transforming into a weapon, Syl's first choice is a sword, before correcting herself and saying Kaladin probably wants a spear instead.
My question is... if the shardblades are "based" on the honorblades, why is there such a size discrepancy? The Shardblades are kind of oversized weapons, whereas the Honorblades (at least the ones we've seen) are smaller. Is there any realmantic reason for the size difference?