I think you're right, that the story is making progress. They need a long runway to build up some melodrama. Izumi's confession section was so drawn out and dramatized that if they did less for the main couple it make the drama seem very misshapen. Also, I think a happy ending for haughty princess Fujishiro would be hard to take if we didn't feel like she had earned it.
Maybe I'm just the exact right audience for this, but I end up hanging on every open-eyed look of surprise, shock, and pain on Fujishiro's face. It's a very, very tense series for me.