SPOILERS for WoR
During Kaladin's fight with Szeth, Syl changes from a shield to a sword to a spear to a knife. At the time of the recreance, why were all of the spren left in a sword form?
On a similar note: can a spren take the form of a projectile weapon? The Radiant could have a massive bow (like Sadeas has at the fight with the chasmfiend) and the spren could take the shape of an arrow, get released from the bow, hit the target, dissipate, and return for another shot).