I actually like how the game looks. I think the way that they've managed to integrate the two styles of the world very well, in a way that I actually quite like.
That said, I still have yet to finish any of hte Risen games and feel that this is probably going to be a game that I should experience after those ones. Would most people agree, or is each Piranha Bytes game different enough that there isn't an iterative build up to each new title?
I dont think so.
Gothic 2 was a big improvement over 1 in many ways.
in Gothic 3 they planned too big and failed.
Risen 1 was again much smaller and worked well, definitely their last really good game, although the last few hours were bad. it became a hack and slay in endless dark dungeons towards the end.
Risen 2 was a huge change in many mechanics, very streamlined and simplified. their worst game in my opinion.
they improved on that for Risen 3 but it was still not received well.
Elex is something completely new now, story and setting wise, but it will definitely be a Piranha Bytes game with all their strengths and weaknesses from what I have seen so far.
I don't think you need to finish any of the Risen games if you want to jump in on Elex. I am mildly optimistic but we'll see.