My guess is that Yuuki is opposed to Japan for w/e reason, and that ends up being the overall motivation, which I said was fine
The merchant vamp faction though, I feel like I want the show to explain to me PRECISELY how economic development is bad, because they used that line in today's episode and it was laughable. If they decide to use some justification like: "we use monsters as slave labour, and Tempest prevents us from getting cheap slaves" that's at least something, even though it's ooc because Rimaru isn't anti-slavery. But you know as well as I do Dialga, that economics is not a zero sum game and increasing the overall production in the world is EXACTLY WHAT MERCHANTS WANT because they can trade more finished goods then.
They did bring up the angels again, which are a funny mechanic, but are probably the only interesting aspect left to play with since the power scaling of the rest of the world is completely solved at this point