That's a pretty good question & I've got a corporate answer to that one - There's even some truth to it
Here goes:
We wanted to make a game where people were going to say - hey, that looks and plays really cool - rather than have a game where people said - hey, that plays cool but it's a shame about the outdated technology. I thought the gamestar preview was very typical of that (the ending where he talks about the outdated tech for Divinity 1). To reach that goal, we had to invest heavily in both our art and technology over the last years, and radically change our approach to development (which honestly was quite chaotic in the past). Our internal quality expectations are a lot higher nowadays and we are very demanding in trying to polish things. So, the different font thing wasn't really done on purpose (actually, it was made by somebody outside the team), but it somehow symbolizes that change and it felt natural to change the look.
