This is a tough one to comment on, mainly because I've seen each camp (loved it, hated it; bring back classics, try new stuff) bashing the other on various online forums.
I will say that it took me a while to get on board with Nexo Knights, but once I did I enjoyed some of the sets and parts and playability. I'm not the target audience, so I can't say how the digital experience helped or hindered everything.
I do applaud Lego for trying new things - in the end it seems like Nexo Knights is a combination of things that went well and things that could have gone better. Some examples:
-
Good: The shield designs and powerups were a neat feature;
Bad: There were WAY too many for anyone to collect that it felt gimmicky, why collect at all if you're not playing the game?
-
Good: New parts and new colors of existing parts that lend well for MOCs;
Bad: Some of the colors didn't mesh well in Wave 2 and the theme seemed to lack some consistency
-
Good: Digital experience (game/show) helped to tie everything together;
Bad: You were left in the dark on many things if you didn't watch the show/play the game. After reading a bit about the storyline it actually helped me to appreciate what the sets were trying to aim for
In the end I like the variety of new things that we can add to castle MOCs. As a theme though it was a miss for me, but again I'm not the target audience. I did learn some neat techniques from the sets I did pick up, so I was happy about that, and the concept art for the original pitch certainly looked cool.
At the end of the day not every theme that Lego puts out will be a homerun... and that's ok! If it helps them make the next theme better, then we as a community should theoretically be better off for it. Maybe, just maybe, they can pull inspiration from what came before (throughout all the castle years/themes) to create a new line that strikes gold! The other thought too is to do a one-off retro inspired set to test the market. Who knows... the beauty of Lego is that they're willing to take risks
For a new castle line, I think it would be great to feature a civilian series in line with MMV and the Mill Raid sets. If done right it could incorporate elements of action / conflict that they like for castle sets and also expand the range of a standard castle line - I imagine these could fit into multiple castle themes, again, if done right