1. Seras can be killed. She just resurrects at the end of a plot unless a point is made to decapitate her, incinerate her, and scatter her essence to various crossroads.
Which is a thing that should probably be a perk, similar to what Icarus has. Actually, this goes for 2 and 4, as well as Regeneration, Superhuman Strength/Speed/Senses and Reflexes. These are definitely things that you should be taking as a perk, and not as abilities that you have.
3. She isn't a normal vampire. Her "abilities" are situational at best. They can be locked down.
Shapeshifting and Intangibility are hardly situational at best, and several other abilities are generally good in combat as well. Also, locking them down is a process that doesn't seem to be explained on your sheet.
4. Her clairvoyance ability means that she is immune to Illusions, Fear, and stuns. This doesn't mean she can't be poisoned, cursed, burned, frozen, etc.
6. If you really wanted to take her HP down fast, Hit her with silver or bleeding status. Her HP regen won't do shit for dicks against bleeding and silver
That's not how disadvantages work. You can't say that being able to be poisoned, cursed, burned, frozen, etc. compensates for her being immune to illusions, fear, and stuns since every other character is weak to that sort of stuff. While Seras is weak to silver, that's a weakness which is unlikely to be used except in certain situations. Most people don't carry around silver weapons for use against vampires, and having the GMs include people like that in their adventures just to deal with Seras doesn't strike me as very fun for anyone.
5. As for her increased SPD, STR, she isn't a normal Human. She is a lot faster then most humans.
As is everyone else. The problem is that other characters don't get random bonuses for not being human, so why start now? And if we did start doing that, then it wouldn't be fair to everybody playing a human in the first place.
7. As for stat points, she should only have 114 right now. Looking back over it she has 111...
Basic math says that 15 + 14 + 20 + 20 + 25 + 17 + 10 + 10 = 131. I don't know where you're getting 111 from.
8. If you think something needs nerfing for a tank character, i want to hear it.
I'm pretty sure that we've told you what needs nerfing. Though it's less nerfing and more 'getting her into line with everyone else's power levels so that it's more fair'. Obviously RotMG has never had the best balance in the world, but it's pretty obvious that Seras is OP and needs to be fixed because everyone else is nowhere near as close to her power levels.
Also sorry if I sound too mad/confrontational. After the v2 thread this kind of stuff annoys me to no end.