As far as feeding/starving dictating your power level, that actually made sense to me. For any other flaws the game has, I though Bethesda did a great job at balancing things. Everything has a pro and a con. Feeding reduces sun damage and keeps people from attacking on sight (at least before Dawnguard), but it weakens your abilities. You can let yourself starve, but you'll take more sun damage and your "mask" disappears, forcing you to stay away from communities. In a game that has little in the way of effects and consequences in quest decisions, I like that there are some in other ways, like with vampires. It's also why I have no problem with not being able to block while dual wielding.
As for feeding hurting you... that sounds like a bug with your game, because I've never had that problem.
Look on the bright side.
At least they don't sparkle.
Vampires become more "vampire-like" when they don't feed.
What's hard to understand about that?
because that's a trait only the cyrodillic bloodline of vampires are supposed to have.
I dunno, they're all creations of molag bol. The ones in Cyrodiil just made an additional pact with Vile, right?
I don't know the specifics but in in game books its written that cyrodillic vampires are the only type that can blend into society because when they are fully fed they look perfectly normal for there original species but when they haven't fed in a while they look well ghastly and clearly not a normal living individual much like how other vampires in the elder scrolls universe are supposed to appear.
Vampires were created by molag bal,but there are many different strains of it for different daedra. There are clavicus vampires,namira,mephala,boethiah,etc.
Yeah that is their clan trait when they feed they look more human but the common trait all vampires have is the whole feeding and not feeding thing. Its just that the vampires in cyrodil got an extra perk because of their deal with Vile with the whole turning human more human thing hence why the volkihar don't change no matter how much they feed. I assume before the deal with vile they looked like their "no blood" state. The whole vampire feeding is simply a system to help the vampire aquire blood hence they get more abilities the longer they go without blood but their weakness hightens because of the lack of blood but they get more tools to help the aquire food so they don't go insane.