This would be a lot of work for extra companions (unless they added some in during Act 3 or something). It's a big enough update that it may be expansion-worthy if Larian is so inclined (or sequel worthy, in the same way that Baldur's Gate 2 was to Baldur's Gate 1). That said, I'd definitely agree that additional companions in general would really be amazing. I would love to see a companion for each class (not to be confused with subclass), even if some didn't have quite as deep a storyline as the ones included.
For extra playable races, goblin and ogre would be a little hard to include, mostly because they're monstrous by nature. I don't see most people you interact with treating them the same way as they would even a drow. That's not to say it couldn't be done, but there are definitely story elements that would really force your path for either of those races.