Based on that video as it shows a lycanthropy perk tree, there should also exist one for Vampirism. Of course, none of those exists...yet...
I feel the vampire should become even stronger per stage. Seeing as vampires are supposed to be beings of legend that are more powerful than regular humans. Also, these effects would take place beginning on stage 2 and up only to regress to when the stage is lowered. If a skill does not level, it is activated during stage 4.
- Fortify Health, Magicka, and Stamina by 200. So, they are naturally stronger in combat.
- Fortify carrying weight by 100 per stage totalling 300. So they are naturally stronger.
- Fortify unarmed strength by 20 per stage totalling 60. So they are naturally stronger.
- Fortify resistance to regular weapons(non-silver or non-Daedric) 20% per stage. So they are naturally harder to kill.
- Fortify sprinting speed by 10% per stage totalling 30%. So they are naturally faster.
- Fortify Vampiric Drain by 10 per stage totalling 35 per second. So special abilities are stronger.
- Fortify spell strength by 50%. So all spells cast by vampires are naturally stronger.
As for werewolves, they become a liability for some 25 levels, but that later fades away from how I've played the game as I am level 60. The skill tree should include:
- Fortify resistance against regular weaponry by 20% three times. They are naturally harder to kill, but still weak against silver and Daedric weaponry.
- Fortify claw strength by 25% three times.
- Fortify Magic Resitance by 10% three times. They have a better change against mages.
- Fortify Howls by a factor of two(e.g. Howl of Rage now affects enemies up to level 50)
- Increase natural Health and Stamina gain by 200 totalling 300 extra.
- A perk that allows them to do take things as if they were non-transformed, such as opening a chest to take items or looting corpses.
As a bonus, if the player has fed, when the player regresses, blood should be on the body and be on for one in game hour, if the player comes into contact with NPC, they should comment negatively about the player's appearance if not also attack on site.
Those seem to be what a werewolf or werebear should be able to do. With the tree given, it would be along the lines of vampires are good for things in general as even a low level player would be fierce and lycanthropes would be great when used. Both at the highest level would be rather strong, but werewolves stronger and faster, but vampires would be better for things in general due to their use of weaponry and magic.