It just might be that the Tenseigan is the warrior counterpart to the Rinnegan's mage status.
I think it's good that the Hyuugas are getting a power up, Because Hyuugas are awesome. So i'm all for it, as long as it doesn't have any outlandish destroy the world in one move abilities, in which case we can just put RP rules up for it so that everyone isn't strong-arming it
I feel like it's going to have a hand in bringing down the moon so we may need to nerf it.
No giving up 6 resets as well have having full Byakugan is a good trade off for getting power that is almost equal to Naruto's chakra cloak.
I hate to say it, but it would be unfair to Bocc if every 4 reset character was able to match his mastered Biju cloak's ability. It should require 10 resets minimum (4 Hyuuga, 6 sage) and the inability to use things like Rinne/Sage. Just to balance things out. Just a suggestion though.
It's pretty obvious that it will require Rinnegan resets to use it at full power, after getting four Hyuuga resets. What that full power is, is still somewhat unknown. But you get to have a fancy chakra mode.
And ten resets seems extremely fair, when considering that the Rinnegan lets you kill people and take their knowledge upon contact, and also bring down meteors. Throw in the 2 eyes > 1 rule for power-balancing and it would be fine.
Though the whole point behind bringing down the moon in the movie, was because the Otsutsuki clan served as the guardians of the Gedo Mazo's prison, the moon itself. And as such, they literally lived on the moon. This started with Hamura, and would end with Toneri since he's basically the last of his clan and has no purpose now that the events of Kaguya's sealing is now in another dimension. So yeah, there was a ton of butthurt behind bringing down the moon. But Toneri had a device to do that first for him, until it got destroyed by Naruto and Hinata. After which, his Tenseigan finally awakened after getting used to his new eyes (Hanabi's Byakugan) and used that power to continue to bring down the moon. Final battle happened soon afterwards, and Toneri loses. To rub salt into open wounds, Hinata literally just plucks out his eyes just to bring them back to Hanabi.
It is this very last part though, that follows the requirement of needing Otsusuki blood/DNA to not only awaken the Tenseigan, but keept them in that state as well. In the epilogue, Hanabi is shown with just her normal Byakugan eyes. One would think that they would be plug-n-play like the Rinnegan, but I guess Kishi didn't want to stain the Hyuuga's prestigious reputation with in-clan eye-snatching shenanigans. We already know how well that went with the Uchiha in the series, and here.