I have completed the vampire faction, now I'm progressing through the Dawnguard yet it's exactly the same quests so far. I don't feel like I am doing anything new. It reminds me of the Civil War, two different factions yet the same content with a different name slapped on it.

Well its 2 groups going for the same goal. What did you expect? If group A and group B need something from location 1, then why would group A or group B go anywhere else?

you would think their goals would be different... and the outcome remains the same regardless... so the only choice is which castle do you want...sad really ... still enjoyed it. but left feeling unsatisfied and hungry for more...

"More content? Nah it's ok Bethesda. I can settle for copy-pasted work, thanks!! "
Seriously why would you NOT want different questlines? The guilds have the same questlines BECAUSE Bethesda designed them that way. To say it makes sense for the story is kind of a moot point, as Bethesda can take the story in any direction they want, but chose an easy route where both decisions intertwined and resulted in a very similar product.

This is exactly the words for this dlc copy-pasted work.