Well, the main issue is that, without added spell support, there is little reason to consider a heavily paladin-based DD over a split Paladin/Sorcerer. Paladin 2/Sorcerer 3/Dragon Disciple 4 has a lot more going for it, and if you want to continue down the gish path, you now qualify for Eldritch Knight, so you can keep your BAB up. This way, at 9th level, while your BAB is a tad low, you have access to 3rd level spells like Haste, Heroism, and Fly, all of which can support the party, or close the melee gap with the raw Paladin build, while also giving you access to more 2nd level spells, a better Arcane Strike damage bonus, and it opens up some of your feats.
If you are insisting on using a one-handed weapon, pick up a mithral light shield/buckler. It's an easy way to keep up your defenses. If not, grab a two-handed and put that strength to work. Instead of Dodge/mobility/spring attack, consider Arcane Strike, Furious Focus, Or something else with more direct benefit. Swap out one of your traits for Magical Knack. That caster level boost is too important not to take.
With your stats, consider grabbing a reach weapon and Combat Reflexes. With Enlarge Person up, you cover a huge area with lots of threat. If you really want a companion, swap out your 1st level bloodline power for a familiar, and consider the Protector archetype for it. It's a solid utility/defensive boon.