1) Putin did not address the economy well. Rising commodity prices addressed the Russian economy. No structural problems were addressed, and until they are, Russia will falter every time commodity prices go down. What happened to the scientific prowess of the Soviet Union? Putin has not restored that. Russia is not a leader in any high-tech industries, despite what Putin thinks.
3) Putin is asserting Russia's interests in a typically moronic Russian manner. That is to say, he is trying to set Russia up as a Great Power and an ideological competitor to the West. But it doesn't have the population, resources, or technology to do this, so all it is doing is spending its money wastefully on these vanity projects. I mean, take something like selling missiles to Syria. It gains Russia almost nothing (some small money in arms sales and close ties with an country that still leaves Russia without any real leverage in the Middle East), but Russia pursues it because it is a poke in the eye to America. Much of Russia's policy seems more geared towards annoying the US (to prove that Russia can do what it wants) than doing anything useful for Russia.
Let me put it this way. In 20 years, China and India will be rich and fully integrated into the global system. Russia, which 20 years ago was far ahead of both, will likely not be. For that, Putin needs to answer.
4) What Dell said is standard business/political talk. It's a polite way of asking, "Is there anything we can invest in that would make both of us rich?" That's why politicians go on foreign trips trying to drum up business from investors, and why countries fly their own investors overseas to meet with foreign countries to solidify relations. Even if there are no specific opportunities for Dell right now, it is incredibly stupid for Putin to respond this one. It just sends a message to foreign investors that they are not wanted in Russia (a message already sent by Putin's actions to seize foreign investments in Russia's oil). How does eliminating foreign investment help the Russian people?