I think personality and character backstory matter more then the race of the companion IMO. Say you got another drell and a batarian on the team. Wouldn't you want them to have a more unique personality then just their racial background? Like if your batarian squadmate just had all of Kaiden's dialogue, wouldn't you be a bit miffed that this is just a Kaiden clone but with 4 eyes? Or if you had a drell squadmate who was exactly like Thane, isn't that no fun?
Now, I know why I would want a batarian squadmate. The society they come from would be interesting to learn more about, from a day to day point of view. Issues such as classism, autocratic rule by a single state, and being essentially a third world fighter could all be awesome to explore. The potential of a character breaking the mold of expectation as well could be cool, like a rebel batarian who was opposed to some of the slavery practices. Or one who wanted to depose the hegemony for ruling over everything else. You could also have one that doubles down on being an ******* and have another Javik or Zaeed type, which a lot of people seem to enjoy. There's a lot of potential there, just as there was for characters like Wrex, Garrus, Jack, and even Jacob and Miranda. Since this is post Me3 we can even have them talk about their new place being hit hardest by the reapers, if that will even matter in Andromeda's setting. It could be an old wound that they can never quite recover from, like the Quarians and Rannoch, that they lost their homeworld and people to their own pride.
There is a lot of potential there, that I think should be taken into consideration over just having them being a Batarian, and that's it. There's a lot more then just physical appearance that should go into a squadmate.