Working on a single, new race takes a lot of time, effort and resources considering how it takes a whole expansion just to add one - and I imagine the cutscenes play a major role in why it's not very straightforward. So with all that said, I can understand why they'd be reluctant to spend all of that effort designing a whole new race and pouring tons of effort into it just so 4% or less can enjoy it while the other 96% moan about how SE made such a terrible decision and that it was an awful addition etc etc.