I was having a tough time in a fight and decided to try a new party composition. My usual party is at level 16, I brought in Fassina, and found out she could only reach level 13 when I leveled her up! I already knew she would have a bit less experience, but that is ridiculous. You primarily get xp from quests and there are a limited number of quests, so trying to use her or any of my benched companions at this point would be a massive disadvantage.
What makes this truly baffling is that you can hire adventurers (which you can min/max to your pleasure) only one level below your max. So I'm not being so heavily penalized for trying new companions, but only for trying the voiced companions that Obsidian created. I cannot get my head around that decision.
I don't understand why there are experience penalties at all in this game. How does it enhance the experience? Why should the developers dissuade you from experimenting with your party even slightly? I feel like I must be missing something.