We really have no idea what TOS would've looked like, because Paramount shot another pilot, "Where No Man Has Gone Before", and TOS still wound up looking different than even that. Remember, WNMHGB had no Uhura, no Chapel, no Rand, no McCoy, and Sulu apparently wasn't stationed on the Bridge at that time.
I will say this: the "Cage" uniforms were a little less obnoxious on the women, even if the male TOS long-sleeved T-shirts looks so cool. I suppose the counter-balance would've been that "Number One", a female character, served as the ship's XO.
All in all, Jeffrey Hunter would have made a memorable captain of the Enterprise.
Another wrinkle to consider: if Jeffrey Hunter had continued on for TOS as Capt. Pike, TREK might've died with him in 1969. That Hunter died so young, with so much promise, never ceases to amaze me. He joined a long line of "immortalized" brilliant entertainers like Richie Valens, Jim Morrison, and Janis Joplin who all had a bright future ahead of them.