It's laughable to think a country could solve any of those things through stricter legislation; that will simply encourage those companies to move more of their operations to jurisdictions with more advantageous laws/taxes/labor/etc.
So how do you "level the playing field"? One way would be bringing those advantages to smaller companies through businesses that exploit those same loopholes / tax strategies, providing them as services to companies who otherwise couldn't afford doing it themselves (i.e., exploiting legal loopholes as-a-service, international tax strategies as-a-service, etc).
Or, you embrace the global economy, specialize in what your country can do most efficiently (hint: it's not manufacturing anymore in the US), and make it advantageous for companies to keep operating domestically. You lower taxes for everyone, so even the companies with few resources can enjoy the eased financial burden of taxes that normally only the big guys could avoid. In short, you compete globally rather than stick your head in the sand pretending that your country is somehow isolated from the rest of the world and you can fix everything through legislation.