The losing companions thing is really grim for the evil path IMO. Particularly if you are keeping some of the datamined stuff in mind:

Losing access to Wyll, Karlach, Minsc, possibly losing Gale, and almost certainly losing Lae'zel or Shadowheart (apparently a DC20 check to keep them both) we don't know about Helia yet, but she's supposedly one of the 'good' companions as well

Plus, you lose out on Gale and Shadowheart's romance options if you play evil. If you are playing evil, it looks like a distinct possibility that you could be reduced to less than a full party of characters before you even head out for Moonrise towers. That's not even taking into account that the player themselves might be playing one of the origins characters. Taking it to the extremes, if you are playing as
Asterion, with Shadowheart killing Lae'zel, and losing Karlach, Minsc, Gale, and Wyll when you side with the goblins, leaving Helia as a wildcard
, it looks possible that you could easily end up with only one companion, and one romance option.

And for what? The only real tradeoff you get for siding with the Tieflings is that Minthara dies, but Larian hasn't even confirmed that there will be non-origins party members yet, so we just can't take for granted that she'll be available to plug into the hole where our missing companions were.