The shield and bsword combo is kind of the point....I just wish there was a way to make it not-so-useless. Whats the application here? I'd imagine better tactics and tanking? certainly not dps by anything I can think up.
You aren't going to maximize dps with a sword and board build, but there are so many things you can do with a well-built Vanguard that the real question is what it is you want to do with the build? You then need to make sure it's a good fit.
The way to get the most dps possible out of vanguard is to lean in to debuffing. In the case of Vanguard you can get a debuff on your weapon and a shield which significantly improves your boss beatdown time. I also use shattered device for a bit more debuffing and crusade is another boost.
I am currently using an Undying age bastard sword and Palisade for bosses with dust on the sword and vacuum on the shield. Against mobs I use Ignition with paralyze and a golden age large shield with guardbreaking.
I go T5 KOTC and Vanguard capstone for sustained attack speed - with 0 points in tank tree. I know Mechgraber prefers to go T5 and Capstone KOTC with a deep vanguard splash and a splash to VKF for haste boost.
I found the build to be one of my favorite dungeon clearing builds because it clears mobs fast with the paladin AOE and quickcutter - and it beats down bosses faster than a caster, but not as fast as top-tier dps. It's an extremely survivable build with high saves, prr, mrr, ac, hp. It's not a great build for raid dps, but it's wonderful for soloing some raids like VOD and short-manning others.
At the time I built the character Palisade was the only shield with debuffing, but now you also have the option of using a Cataclysmic shield if you prefer that over the Palisade. I am happy with the build so not in a hurry to upgrade gear, but there are clearly some upgrade options with the newest gear.