The kind of tax manipulation you talk about may require changes to the tax code. But the common beliefs that capital gains are only for the rich and that taxes on them only affect the rich are folly.
To increase capital gains (and dividends, for that matter) across the board would have huge affects on the middle class as well.
Mutual funds, 401(k) plans and other investment plans have trillions of dollars invested by the average worker. These funds are also subject to capital gains and dividend taxes. Over many years, these taxes can amount to a lot of money lost by investors.