As for humans, nothing in Sera's background (what we know at least) suggests she holds a particular animosity towards humans. She doesn't like 'bigwigs' which does include nobles but it would also include the Inquisitor (dwarf/human/qunari/elf). I think that will be a hurdle to get over if you desire any form of relationship with Sera (friendship/romance).
This is one thing I'm particularly looking forward to. Since it's pretty much a given that Sera and the Inquisitor won't see eye-to-eye the first time they meet, it makes you wonder what kinds of things we will have to do to get past that hurdle.
Ideally, I'd like it to be something that we can build upon as the story progresses, as opposed to just doing her a favor ('loyalty' mission?) and automatically becoming besties with her.