So you want an additional spell to cast for the sake of having an additional spell to cast...
Except you run the risk of creating a balance clusterf*ck if you make traits accessible to more than just the job they originate from.That being said, I would rather see traits that effect your subjob abilities. Most jobs have a select few abilities that they gain access to via their cross-class. Paladin is not the only one who is stuck with less than stellar spells and some Jobs/Classes could use traits that change/buff/etc to make these abilities more fun and useful. Traiting Pro/Shell would be a step in the right direction.
As I mentioned, PLD is designed around a modern MMO tank with utility on the side, where utility going unused does not break the job in any way, as the foundation it is built on is very solid.Yet I would like to see traits that enhance abilities specifically for their use on other Jobs. Having a trait that changes Cure to cost more, produce more threat (1:1), change its potency to be effected by attack power (like the change to Second Wind), change the cast time to be faster to allow for movement and change the recast time. The spell can be the same but function in a manner that allows it to be an intricate part of the Paladin kit.
We don't need cure as a mainstay for hate when we have the needed hate tools to do our job as tanks. We're not D&D paladins or WoW paladins; our faith does not manifest through awesome divine power with which to smite our foes. We don't summon giant glowy hammers out of the aether to hit people on the head with. We're par the course of Final Fantasy paladins, as they are knights with weak white magic. We currently fit that bill to the dot.