Does it have to be white knighting or can personal preference factor in here. "More important" is subjective to HOW important a person considers either feature. I would likely play a new class to try it out and who knows maybe get into it, but I also don't think the game necessarily NEEDS one right now. Through Allied Races we've also just had 10 races added to the game since the end patch of Legion, so:
A - I really don't think getting additional races at this time is important at all
B - My personal speculation on the chances of at least another pair of Allied Races showing up throughout SLs lifecycle is about 100%.
So even if I consider class design and increased customization for original races 'more' important, that's also not saying much given I find the other options not very important at the present moment for the game.