Opinion

 LISTEN!

I think the Chameleon Arch has a bigger unrevealed role yet to come in the series. Despite the similar attributes in physiology, why would Time Lords from Gallifrey choose to be normal humans? They could have been anything - Augmented humanoids, cyber- humanoids, converts and hybrids, other human-like species form other planets. So why Earthlings? Only the Doctor has an unexplained fascination with Earth. Which is why other rogue Time Lords like Master and Rani or the Meddling Monk or his enemies like the Daleks might consider targeting Earth, to torment him. But why the rest?

Also there was once a theory that the Type 40 TT Capsule (The Tardis) the Doctor uses, is itself a Chameleon Arch. When the fandom of Whovians were introduced to the Division, with inexplicable connection to the Doctor, it was theorized that maybe the Doctor was once the employee of either the Division or a body like the Celestial Intervention Agency (C.I.A), who erased the Doctor's memories corresponding to something big and important, and installed a Chameleon Arch in his life, to make him think that he always had a regenerative cycle limited to 12 and never even had another life before that.

Time will tell.....