Skyrim again at 50%-51%

I don't think it's too bad, it just could be much better. There's so many places that are HUGE and you would think adding more places to the world would be awesome, but it really isn't. In the new maps everything looks exactly the same and trying to explore every bit of it gets boring very quickly. There's a few side quests to these maps, but because they're so difficult to navigate, to me at least, you kinda need some sort of walkthrough to find anything. The new companion you get, Serana, is dumb and annoying as hell and once you've finished the Dawnguard guest, you'll be glad to get rid of her. But don't get me wrong, it add few more playing hours and some items that you can get from the quests are really neat, for example one quest gives you this circlet which allows you to hold to powers for any standing stones. Oh, and you can get a really neat spell which gives you the ability to summon a horse which cannot die. You can summon him over and over again. To me, as I'm playing conjurer mage, this spell is very useful. (plus my horse always dies and I'm too poor to buy a new one) Also, in this one place you can get infinite amout of expert spellbooks (or armor or weapons too) from doing a continuous quest to this one guy. So I would say buy it, but don't for the full price, it's definitely not worth that.

mods can do some pretty amazing stuff like increasing dragon difficulty, make new places, more creatures etc...

Wow, seriously? Moddding is a essential part f the elder scrolls games. Modders make a giant lot of things and some are even copied by the devs(you know the hearthfire dlc? Yeah, all the things that dlc were made by modders before, for free)
Mods can put the game looking better, mods can patch out bugs and glitches that bethesda never has remembered to fix.