Specifically speaking about the Dubai route, I definitely agree that the additional capacity brought by Emirates’ daily wide-body aircraft is significant relative to the probable demand/market size. Thus, I would not be at all surprised if the pricing on said route faces pressure as supply increases when Emirates begins operations. Based on Middle East traffic data and interim reports, I would also suspect that Helsinki-Dubai as an individual route has been quite good for Finnair, as load factors rose high after the termination of Qatar’s flights from Stockholm and Copenhagen, and in my opinion, Middle Eastern average yield levels have also been good. Even though Finnair is a network carrier that optimizes the whole, there have been no onward routes from Dubai and, on the other hand, little potential for connecting traffic via Helsinki purely due to geography, so I believe analyzing the individual route is relevant.
Regarding connecting passengers, I also think the competitive landscape is exactly as you described, meaning primarily Finnair/Qatar with a transfer in Doha versus Emirates with a transfer in Dubai towards Asia, Africa, and Oceania. In direct traffic to Dubai or the United Arab Emirates, it’s then Finnair versus Emirates, and in fact, it seems Norwegian is also in the competition with a few weekly frequencies between Helsinki and Dubai operated by narrow-body aircraft.