I am replaying through Original Sin EE and feel like there was a missed opportunity with the various animals that you can talk to via pet pal. It would have been really awesome, if you could persuade the dogs, deer, even sheep through dialogue/persuasion or via a completion of quests to join you permanently on your journey. The way I figured it could have worked is like this:
They would have taken the place of your summons; you could not control them outside of combat, they would have no inventory of their own, but would scale with your level and whenever you would like to switch them out - or deploy a more powerful summon in combat, they would have been sent to the End of Time and would stay there. It would be a tiny addition, that I personally would really appreciate. It is a small thing, but an animal companion following you outside of combat makes a player feel more unique - especially when you would have gained such a companion through quests or persuasion.
Now I assume that in OS2 there is going to be some sort of Homestead, an equivalent of End of Time where you will be storing your items, cutting hair, crafting and the "storage" of regular companions. So I feel like this concept could work in OS2 as well.
I am not trying to say that you should make the combat summons permanent, even outside of combat - the incarnates, spiders, etc would still be combat only, but they would more powerful and versatile than these animal companions.
Anyway, just my two cents. I love both of these games, Larian, you have created something beautiful and lovely. Thank you!