Do that and full blown civil war would erupt in Ukraine. Ukraine would become half as big as it already is and would become a failed state. A third of Ukrainians speak Russian as native language. They would never join NATO.
That's a fake poll done by the illegal putch regime in Kiev, or a poll in which people are afraid to voice their true opinions out of fear of being arrested by the putch regime in Kiev. Look at the presidential election voting numbers of 2010. 90% of Donetsk and 89% of Lugansk voted for Yanukovych, who isn't even that pro Russia. Over 90% of East Ukrainians do not want to be part of Ukraine. They'd rather be independent or better yet, be part of Russia.
Russia is a rich country. Over 17.1 million square kilometers and only 145 million people. That's a much lower population density compared to Saudi Arabia. Crimea itself has a lot bigger territory than Israel with only 2 million people compared to Israel's 8 million (not including West Bank and Gaza Strip). Russia has the highest natural resources and material wealth per capita, except maybe compared to Canada.
Your economy means nothing. The US has 18 trillion dollars of debt. Money is only a number in the bank. Only material wealth per capita is the correct measure of economy.