1) that type of architecture was developed when Slavs were Christians.
2) It was heavily influenced by Byzantine achitecture.
3) It was built in shape of cross.
4) It is Chuch
Yes it is Christian architecture. Slavic Christian architecture.
Slavic culture is called the wooden culture. When talking about Slavic culture, we must be aware of the fact that the core of Slavic culture was and still is pagan. No matter if you like it or not. Your logic says that 100 years ago the Christian churches in Slovakia were Pagan, because people called it Perun's houses. Yes, it is well recorded. Christian missionaries took over so many Slavic pagan stuff because they knew, people would hardly give them up. And many pagan temples were rebuilt to churches as the archaelogy and legends say.
I know, you're a priest, you will never admit it.