Transformations in “AGENTS OF S.H.I.E.L.D.”

During my viewing of ABC's "AGENTS OF S.H.I.E.L.D.", I noticed that between Seasons One and Three, certain characters underwent a transformation or acquired powers through certain circumstances.   Of the four characters mentioned below, three of them were transformed, thanks to a mist from a crystal called Terrigen.  This led them to become Inhumans.  The fourth character had been transformed via science experiments conducted by the terrorist agency called HYDRA.  I also noticed that at least three characters also endured a serious physical transformation.  Here they are:

TRANSFORMATIONS IN "AGENTS OF S.H.I.E.L.D."

Mike Peterson - A civilian who had experienced a severe back injury on the job.  A group called the Centipede Project (which was controlled by HYDRA) recruited him to use their Centipede serum.  The latter acquired new superpowers, but it formula also affected his psyche.  The team of S.H.I.E.L.D. agents led by Phil Coulson, saved Petersen, when HYDRA turned on him.  After serving as a S.H.I.E.L.D. agent for a while, Peterson was captured by a team of HYDRA agents led by S.H.I.E.L.D. Agent John Garrett, who was betraying the latter.  Garrett and HYDRA transformed Peterson into the Cyborg known as Deathlok.

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Raina - A scientist who believed there were people in the world with the potential for special powers.  She also believed that she might be special, herself.  Due to this belief and her search, Raina was willing to work with HYDRA  Raina was eventually exposed to the Terrigen mist inside an abandoned Kree settlement discovered by Coulson, and transformed into an Inhuman.

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Dr. Andrew Garner - He was a neurologist and forensic psychologist who worked for S.H.I.E.L.D.  He was also married to S.H.I.E.L.D. Agent Melinda May, until a traumatic event that she had experienced, led to their divorce.  Dr. Garner and May eventually reconciled and embarked upon a vacation together.  Upon their return, Coulson asked him to examine a book on the history of Inhumans, written by former Inhuman leader, Jiaying.  The book turned out to be a trap for any human, who was exposed by the Terrigen mist from a Terrigen crystal hidden inside it.  Instead of dying, Dr. Garner's latent  transformed into an Inhuman eventually named Lash.

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Daisy Johnson aka Skye - She was a talented hackvist who was born to future Inhuman leader Jiaying and American medical practitioner named Dr. Calvin Johnson in a Chinese village.  Not long after her birth, HYDRA agents raided the village and kidnapped her mother and a few village elders.  Dr. Johnson left baby Daisy in the hands of trusted villagers in order to find his wife.  S.H.I.E.L.D. agents investigating the massacre found Daisy and brought her back to the U.S.  After living in an orphanage and a series of foster homes, Daisy, who called herself Skye, became a hackvist who exposed the secrets of the U.S. government.  Phil Coulson's S.H.I.E.L.D. team eventually caught her and recruited her into the agency.  Over a year later, Daisy found herself inside the remnants of the Kree City with Raina.  She was exposed to the same Terrigen mist as Raina, and acquired new powers.  She eventually acquired the nickname, Quake.

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Of the four characters mentioned above, S.H.I.E.L.D. Agent Daisy Johnson is the only one who did not endure a complete physical transformation.  She is also the only character who is not portrayed by an actor/actress of African descent.

So, could someone explain why three characters portrayed by actors/actresses of African descent had to undergo such drastic physical changes when they became enhanced beings, while the fourth character - someone NOT of African descent, only underwent a name change and haircut when she became an enhanced being?