Natasha and Skye have nothing in common. You could make a case for Natasha and Melinda, maybe, but in general I think 'Character X is just like Character Y!' tends to sell both characters short. Two characters shouldn't be exactly the same, that's bad writing.

I stopped watching AoS after episode 3, but it seems like the writers aren't quite sure what to do with Skye? Everyone else serves a function on the team, and Skye is sort of... there. If I find myself disliking a female character I try to examine why I dislike her, to see if my dislike is legitimate or if there's internalised misogyny going on. Usually I come out neutral towards the character or even liking her, but with Skye... she's not as dull a character as Ward, but she's pretty poorly written.