After Alara leaves the series, she's replaced by another Xelayan female with a bit of an attitude, Talla. Other than super-human strength, which is clearly an asset, what are the both in-universe and out-of-universe reasons for replacing Alara's character with such a similar one?
Out of universe answer is the only possible one here.
Halston Sage wanted to leave the Orville, officially no reason was given (Source), possibly because she and Seth McFarlane broke up.
They did the Episode "Home" to give her an exit episode with room for return. Presumably the scripts going forward require someone to open Ed's pickles so they replaced her with another Xelayan with a comparable personality.