The portion of the quote that's talking about Bless is referring to BG3.
Originally Posted by interview in Dec, 2020
This also goes back to when we first worked on Divine Divinity and Beyond Divinity – we had a very active forum on Larian.com, and we had a small, vocal fan base. They were constantly giving us feedback and ideas, and when I think back on those days,
[the previous is about DOS/DOSII, the following is about BG3]
what we’re now doing in Early Access is similar, only a thousand times bigger. We’re getting a lot of feedback and a lot of ideas now. One thing that we learned from the statistics is that people are completely uninterested in a lot of buffing and debuffing spells – we have stats where you can see how many people are using what spell and how often they’re using it, and that made us realise every magic spell that we put in an RPG needs to have this ‘oomph’ factor. You have to want to click it, or you’ll never click it. You cannot sell a bless spell to people. It’s boring. They don’t care – they want to see fireworks, they want to see damage.
[Below is returning to talking about DOS/DOSII]
If you talk to someone about balancing in the Original Sin games, they’ll say the buffing and debuffing is overpowered, but we make it overpowered on purpose because otherwise people are not going to click it. We make them want to click it. We keep on changing the description and the balance until we see in the statistics that usage of that particular spell is going up. So yeah, we really learn a lot of our own game by putting it in Early Access.
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The portion of the quote that's talking about "making [buffing and debuffing] overpowered on purpose" is about the DOS games.