I actually accidently bought the favor item right below blood of the fallen on accident, crimon vial i believe, not sure though, and i really liked the way it worked, it isnt as useful in the beginning but towards the endgame is becomes very useful.

Interesting ide,a but ultimately I think it would cause people to abandon Blood of the Fallen and go back to Swift Anklets or other items and never use Blood again, since no other Favor item requires a game long path to getting the most out of it. Whether or not that's a good thing is up for debate, but Blood of the Fallen makes a gigantic difference early game. Why swift anklet and run when you can Blood and stay?

just make all bonuses 1% or 1 hp and the game will be  perfect

How is it OP? Anyone can choose to either get it or not. What's the problem?

I`m take Blood of the Fallen only if play Oak. For others - Swift Anklets or Amulet of Teleportation is way better.

Blood isn't overpowered or anything, I actually prefer more agressive favor items.

Its not OP its fine doesnt need a change.

Its good at the start if you plan on taking damage and cant self heal. Scales badly compared with other items so becomes redundant later in game.

Not everyone takes it read the thread on peoples fav favor items to see that many other are poular.

I didn't say it was OP, if you read my original post carefully. However I did say there is a problem, and you've just described it perfectly. If the only good response to Blood of the Fallen is to get Blood of the Fallen, then it's a poorly designed game element. (This is assuming the designers of the game want there to be genuine choice concerning favor items.)

Of course you went on to suggest that there are good responses to Blood of the Fallen other than getting Blood of the Fallen yourself. That's fair enough--though I disagree--but here I'm just responding to the line quoted above. You seemed to think what you said in that line negated any idea that there's anything wrong with BotF. What I'm saying is that what you said is exactly what's wrong with BotF.

Can you elaborate on the scaling? 800hp seems significant to me even in very late late stages of long games. 800 out of, say, 11000hp is still an extra hit or two, or an extra burst spell in many cases.

And that's assuming a game gets to such a late stage.

But which other items are better in late stages, and why?

It gives a sizeable health bonus only eclipsed by the more expensive armor items and boots. I'm not interested in +mana pool from the boots because I need helms in every game I play anyway, so it's a very valuable item.

Saying that if you take it, then I can just take it and we're even is blatantly wrong. Stats have different importance to different characters and more specifically to different builds. By making a +stat item better than the other +stat items (like Mard's Hammer for example) you are giving an advantage to the builds and characters that can take the most advantage of that particular stat.

I'm not saying that BotF is necessarily in need of a giant nerf, but with the current system and the power of HP stacking, it's an item that I take nearly every game, with little concern for what character I'm playing, or for what characters my opponents are playing. It's easier and cheaper to compensate for not having something like the anklet (Use wand of speed) than it is to compensate for not having the blood vial. 

And I have to agree with Stacked, there is very little chance of dying early if you take BotF at the start of a game. You can quite happily get nuked twice and walk away with over half health.

You are being confused by the AI.  People do not teleport to escape - you die if you try that.  They run away.

Ironically you listed the only other good favor items (maybe Marn's?).  Half of them are assassin only.

BOTF is fine. Need to buff other items. I'm pretty certain no one takes Magic Coin Purse...

Is Heaven's Wrath AoE or something?