Board Thread:Theories and Speculation/@comment-1872728-20160229033316/@comment-734582-20160320220709

Georgio722 wrote: You're right about them being the first to awaken it in the Warring States Period, but in total there are numerous Sharingan users, Mangekyo Sharingan users, and even Susanoo users. So it's not really that rare if you think about it. Nope there aren't. The Anime took liberties with the Mangekyou. The Manga doesn't show this at all.

Georgio722 wrote: Yet Uzumaki Naruto can rival Uchiha Sasuke. Yet Naruto is a Jinchuriki, and could only rival Sasuke because of that. Purely as an uzumaki he's inferior.

Georgio722 wrote: Yet the Uzushio doesn't put Senju Clan emblem on their outfits. Does that mean they don't respect the Senju Clan? Hashirama wanted people to put the village above their clans. If other clans went about praising them, it would undermine his vision. Plus, Konoha honored them that way. Doesn't mean Uzushio has to copy that as the only way to show respect.

Legendary Super Saiya-Jin 4 wrote: 2. It's only manifested in two known Uzumaki Clan members, the other several characters who are Uzumaki do not have them or they're not known to have them. If it only manifested in females, Adamantine Chains would also be the number 1 most specific Kekkei Genkai in the Naruto verse, as the only KKG to bias gender. I think it's indeed too rare to call it a true Clan KKG.

As to the Senju not being special:
 * they have large reserves and lifeforce just like the Uzumaki. In the Uzumaki it specifically manifested as longevity. In the Senju, judging by Hashi, it manifested as healing.
 * The Senju didn't specialize, rather they were well-versed in many jutsu. They have no easy-to-point-out powers, in gaming terms they had high base stats.
 * The Senju are the only known clan to have Wood Release. Hashirama's the only known user, but they were known as the "Senju of the forest" so obviously it happened more often in the past.

Lastly, the Uzumaki are strong but specialized (fuinjutsu). The Senju are stronger because they're also good at everything else.