One or both of your trinkets should have some form of emergency use or a static ability that can proc. An example would be "The Black Heart" and "Fervor of the Frostborn". They both have abilities that can raise the mitigation of physical damage by about 10-20% give or take.
Plus the thing with Stamina stacking is good. But the Brewfest trinket should be replaced ASAP with something better. Better to stack stamina in your armor pieces if anything and not your trinkets where emergency and static mitigation is needed.
Threat as a pally shouldn't be too much of a problem as expertise just stops parries from occuring with white hits. The misses can be a problem if you have a low hit chance increase (anything below 3% and I'd be worried). Being hit capped is great but only in terms of threat generation. Your main job however is to survive and keep the hits focused on you.
If you're worried about generation, upgrade your shield and learn to love Shield of Righteousness. It is one of the most effective threat builders for a paladin. Anything that improves shield block amount is a bonus for threat for you.
Spec wise, you're all over the place. In the Holy tree, keep the 5 points in Seals of the Pure and remove Divine Intellect. Learn to love Divine Plea and trust your healer in keeping your mana generated.
Remove Divinity from the Prot Tree and finish Toughness and Ardent Defender. They make up your survival skills and more armor means less damage for you. Ardent Defender gives more buffer for healers to react. 30% is more than 20%.
Benediction is okay, but raid would benefit more from Heart of the Crusader. Increase in Crit chance means more raid DPS overall.
Glyphs are a nice choice. If you find that AOE tanking is lacking, Hammer of the Righteous would benefit you more than Righteous Defence.
Hope this helps you out plenty.
Healing is the source of life. Without it, you're left with death.