Russias support for the current Ukrainian leadership is about more than backing the pro-Russian leadership of a neighbor. The current Ukrainian government is very corrupt, and openly so. The families of senior officials openly get preference in buying, cheaply, state owned enterprises that are being privatized. In addition, the communist era system of privileges and advantages for the politicians remains. The problem with corruption is that if the dirty politicians gets voted out of office, their replacements are likely to be conducting investigations and prosecutions. This will make the current Russian leadership look bad. Not just because their guys were dirty, but because some of the dirt will be found on the Russian side of the border. The current Russian government has been going after corruption, with some success, but was unable to get the pro-Russian governments of neighboring Ukraine and Belarus to do likewise.