Fatespeaker's personality is very similar to Sunny's, and that is one of the only reasons this would turn out good.
Starflight needs someone to take care of him, and Fatespeaker is just the dragon for the job.

While I do like Starflight, I do not like Fatespeaker. She is a little too much of a spaz for me. I think she just bother me for no reason in particular.
Fatespeaker seems obsessed with Starflight, almost as Peril is obsessed with Clay.
Starflight doesn't love Fatespeaker in the same way he loved Sunny.
I've even seen people ship Sunny and Fatespeaker together. That doesn't seem like a good match to me.
I really dislike Starspeaker, but mostly because I just don't really care about Starflight. Or Fatespeaker.
I would prefer Sunnyflight, but still.