With stock market volatility returning for the hottest days of summer, investors may be pondering whether it’s too late to rotate into some of the still-cheap growth stocks. Especially those that didn’t really participate in the first-half market rally.The mid-cap surge came fast and furiously. Though the cap rotation may still have a ways to go, the easy money, as they say, has likely already been made.In any case, staying diversified is key to steering clear of ugly sector and theme-specific sell-offs. Th ...