Generally good piece, but I have a few points:

Maintain a diversified portfolio

Completely agree. In fact, I think this is more important than points 3), 5), and 7). Evidence indicates that the asset classes chosen for a portfolio wield greater influence than the investments chosen within each asset class.

https://personal.vanguard.com/pdf/s324.pdf

The bigger a nation's economy, the more money you should put in its stock market.

Exposure to a country’s stock market is not equivalent to exposure to its economy…

http://www.businessinsider.com/sp-500-foreign-revenues-2013-2013-5

Equity diversification without trying to “out-guess the market” may best be achieved by a market capitalization-weighted world equity fund.

The U.S. government gives tremendous tax benefits to those who invest in certain tax-advantaged vehicles such as 401(k), 403(b), or IRA plans.

Roth IRAs are also an interesting option. Maybe you grouped them in “IRA plans”.

You and your spouse should have disability insurance.

This depends. Affluent individuals might be able to use savings, and the U.S. government offers some disability insurance through Social Security.

Disclaimer: This is not investment advice, don’t listen to me I’m crazy, etc.