I don't have time to critique your build in detail at the moment, but the short of it is that I don't agree with a lot of it. I recommend this, though, that I'll be using for Dawnguard.
Nord Paladin: http://skyrimcalculator.com/#138774
It's pretty much complete by level 43. Seven perks is exactly enough to fill out the heavy armor side of Smithing (including Arcane Blacksmith), but I advise against it since we're already using Enchanting. You can train Altertaion to throw five perks into it in order to get 3/3 Magic Resistance, but I also advise against that as it might be OP if you already have sufficient (~50%) resistance, and especially since you'll have high elemental resistance by default (Nord frost bonus + Elemental Protection and wards) and can use the Lord stone (+25% resistance and +50 armor rating).
Anyway, here's the idea:
-5/5 Juggernaut since we're not using Smithing. If you put points in Smithing later, at least you can go around in iron and steel without a helmet and look faaaabulous.
-Enchanting for awesome paladin toys, like extra magicka and magicka regen, resistances, health, and weapons that put a hurting on the undead. Currently, I've got a simple weapon--a Skyrforge steel sword with 10 points of fire damage and one second of soul trap with about 1,300 uses called Soulfire--but you can make better ones eventually.
-Restoration, 1H and shields can be switched back and forth easy for offense, defense, and tanking for your allies and innocent townfolk as well as healing the wounded. Necromage makes everything more effective against the undead.
-Chose a Nord instead of the more naturally defensive Breton for many reasons. I'll probably get back in this thread and explain when I have time, but just trust me when I say that Nords are a superior choice for this build.
That's about it. Very simple, very effective. Currently I'm level 24 and wearing a full set of steel plate armor and my followers are Erik the Slayer (in full elven with an elven greatsword, elven bow and some elven arrows) and Vigilance (in full fur). What with bandits galore and the Thalmor walking around my country like they own the place, finding a full set of armor wasn't difficult. Beyond that, there's always iron, steel and wolf armor earlier on, and with a good shield, they provide all the protection you'll need (at least until steel plate starts showing up). I was fortunate enough to find a banded iron shield with 10% magic resistance on it, and it's been with me since the beginning.
My helmet is enchanted with 33 points of magicka, my armor with 33% faster magicka regen, and my gauntlets with 27% blocking efficacy. I also have a necklace with 13% magic resistance. Altogether at level 24, that amounts for 223 magicka, 190 health, 150 stamina, 23% magic resistance, 50% frost resistance (capped out frost resistance when blocking), 50% fire and shock resistance when blocking, and 243 armor.
I'm pretty tanky on my own and can easily tank for my friends and heal them. I can help put a hand in defeating enemies either with my good offense or just using my massive defense to tank the crap out of them and bash them any time they move, all while healing my health and stamina (for more bashing, of course). I'm competent with a weapon and shield, though I can switch to shield and spell for tanking or weapon and spell for offense, healing and restoring stamina for bashing or power attacks. Against dragons, there are wards and shields (since I have the Elemental Protection perk), but if a dragon is targeting someone else (especially a civilian) with a breath attack, I either dive in front of them and protect them with a ward or heal them from a distance if they're too far. Erik uses ranged attacks (I haven't got many shouts yet), and when a dragon lands, he's mine. I can block its melee attacks and only pitiful damage will go through, and any time it wants to shout, I bash it.
Just today two dragons launched an assault right outside of Windhelm. The guards jumped in and a Khajiit caravan was nearby, so two Khajiit warriors joined the fight. It was chaotic, but I kept all my comrades healthy and warded against dragon attacks any time I could. One of the dragons escaped, but the other one didn't stand a chance without its brother at its side. The only dragon left fell quickly and there were no casualties.

I'm dearly looking forward to joining the Dawnguard with this character. Sure, he doesn't use Archery, but that doesn't mean I can't use crossbows or have my followers use them. Besides, I can't think of a more fitting build to fight vampires with than this.