Vampires may not look like tired, old monkeys but that's the only improvement vampire have gotten from Oblivion. I've been playing as a vampire for a while now and I don't feel like a vampire, I feel like someone who's weak to fire and gets tired for 60% of the day. The vampiric powers are way, WAY too underpowered to need the once-per-day limit, the cooler powers need to be a high level which is dangerous to be due to the weakness to fire, and the vampiric drain spell is just too weak to be of any use. The weakness to sunlight makes daywalking just slightly more a pain than normal and that really kills the feeling of being a vampire and the fact you can only drink from sleeping people is just a pain more than anything else. Vampires don't feel undead at all, they don't even get water breathing, draugr and skeletons still attack, at least they get a raise zombie spell (which I could cast more than once a day anyway) and immunity to poison and disease (which overshadows the bonuses to Bosmer like myself...). NPC vampires still attack the player when a vampire, what did I ever do to every since vampire in the game to warrant them to attack me on site? All in all, it feels like player vampires are weaker than normal characters, petty powers and a weak spell don't make up for the lackluster experience.
Bonuses to health, magicka, and stamina at night (and other benefits) would give more incentive to vampire players to actual play as a vampire, having a way to drain a hapless mortal of blood via a sneak attack or something, and actually having it count as feed to make it worth something would make vampire characters more like hunters than just people who break into your house while you sleep.
And don't anyone say "mods can fix it" because we shouldn't pay Bethesda for something that the community recognises as needing fixing. Mods shouldn't be a crutch but an enhancement to an already great experience, not tools to finish what the developers just left behind.