Hmm, I am split on this issue. On one hand, I don't think Larian should need to stick 100% to the monster manual. Add and subtract some numbers to balance encounters etc. Or straight up invent some variants. Or give a monster some class levels. But on the other hand, it looks weird when a small goblin punches a large bear at least 30 meters into the air. It just feels like wacky fun, and it doesn't really fit with the atmosphere of the rest of the game in my opinion.
And of course gnolls with 3-4 attacks are problematic. I was surprised when I saw 1 arrow barrage down my wife's character in one turn. That being said, they should probably use the monster manual as a guideline. At least those monsters are relatively balanced (although very easy for an experienced group). And then they can tweak the monsters from there, instead of going far off the beaten path right away.
I create lots of custom monsters when I DM, and I often up need to up the difficulty quite a lof (My group is full of D&D veterans). But I am creating my own world, and I do not have to stick to the monster lore of the setting. So there is that to consider too. I am afraid I do not have a clear opinion on this topic.
