Oh no, I can understand defending what you've thought up...
I'm just not sure the class can really wait for the level of development it might take to implement these changes. These are the sorts of changes you'd expect at version upgrade, 4.0 for instance...not something to see come down the pike during the 3.X series...Then again, they did implement Rogue and Ninja during the 2.X series...
Always been a fan of the old adage "Keep It Simple Stupid"...why build something elaborate when something simple will do just as well?
Anyways, for the sake of throwing out my OWN ideas...if I was king for a day, here's what I would change.
Royal Authority - Grants a buff that reduces cast time by 1.0-1.5 seconds (Like Lightspeed off Astrologian, but used on cast). This fixes Clemency, and improves the usability of Stoneskin, and gives us a unique casting style for future expansions and future spells we might be given (Long cast time, reduced by using our melee combos).
Divine Veil - Buffs the paladin for 10-15 seconds, storing 5-10% of incoming healing. Pushing the button again eats the buff and shields allies for the amount of healing stored or a minimum of 10% of the paladins max HP. Yeah, this ones not so simple, but I like the idea of the ability, but dislike the lack of personal control I have over it...fixing that while keeping the flavor was what I would want...Alternatively make the buff increase the paladins max hp by 5% for every heal that lands on him, using the ability again eats the buff and shields everyone else...
Shelltron - Just a personal pet peeve of mine, I'd change this to just block everything over the span of 2-3 seconds and restore MP as it fades. I absolutely despise going to block a Blinding Blade for 13-16k damage from Ravana, only to have the block eaten by a random 2-3k damage autoattack a split second before the tankbuster smacks me in the face...
Sword Oath - Switches Vit and Str like Cleric stance switches Mnd and Int on healers. Higher damage for the trade off of lowered Max HP while you're focusing on hitting hard. Also makes Fending accessories less of a "bad choice" when gearing out...
I would adjust threat values on our threat combo abilities, and I'd like to see Flash a little more "Threatening" than it is...though i imagine that's just a simple change in its numbers. Having it scale would be nice though, just not sure how possible that is. Flash is a bit of an odd duck without any real "damage" of its own.