MCT is a bit irrelevant in this case, no?
And I don't think there's an ask for consequential damages, only the higher EC261 compensation on the basis of this being an itinerary from the EU to BKK, vs. the single leg from DUS to PRG. As well as the refund.
What I don't understand is how can EW provide a refund for flights it didn't sell? Or maybe that's the "consequential damages" and it's less a refund than a reimbursement of the lost ticket value?

Of course the "solution" for the airline is don't cancel flights (or have better contingencies) and you won't run into these situations. From that perspective I support the ruling. I don't think EU261 was primarily designed as a cash grab for passengers but more of an incentivization mechanism for airlines to operate better, no?