Finland is obviously on our list (and had some prep work done while we designing this DLC), but a well-researched and well-balanced focus tree takes a lot of time. We also wanted countries that were in close proximity to each other to avoid one of the main issues with TfV, where the countries were far apart and didn't really interact with each other. So if we wanted to do Finland, we would also have to do Sweden and Norway. It makes far more sense to do that in a future "Swedish War-profiteering" DLC in between two major expansions.
Bulgaria is a different story. It was in the initial outline and had some research done, but was dropped because we felt we couldn't make it particularly interesting - Bulgaria never joined the war against the Soviet Union, and did as little as they could to stay in the axis. When the Red Army arrived at their borders, they immediately switched sides. Compared to the viper pit that was Romanian internal politics in the period or Hungary's desire to see past wrongs set right, it did not feel like it was worth the effort (assume that it takes us between 3-4 dev-weeks to make a focus tree, plus another dev-week to make the art for the country).
As for China: We also strongly considered China and Spain for this country pack, but decided that these two countries required additional mechanics that would take too much time away from the air revamp and AI work to code, so they were quietly shuffled up the line. We are well aware that China is very popular, and they will get their own focus tree. Just not now.
