No one wants Ukrainistan, least of all Vladimir Putin.
Its GDP of $98 billion (in constant 2015 US dollars), down 43% since 1989, falls in between Ethiopia and Angola on the World Bank tables. Its population has shrunk to just 35 million according to the country’s National Academy of Science from 52 million in 1989, rather than the 48 million reported in the official census, because nearly half of the working-age population has left. Its corruption ranking stands at 112 out of 116 countries surveyed by Transparency International.
Ukraine has some gas reserves but Russia has roughly ten times more, far more than it can transport without massive investments in infrastructure. Otherwise, Ukraine has no natural resources of note apart from farmland – and Russia already is the world’s largest wheat exporter.