Tom,
Perhaps we can discuss CAPM and EMH offline, as it's outside the scope of the article. In my opinion they all have merit and imperfections, as each of their creators would readily admit. We have to use the tools in our toolbox as best we can. A bucket method of two asset classes (cash for liquidity / emergency and equities for growth) gets you to the same place as an efficient frontier of two asset classes. One challenge with the bucket approach is that the amount of assets required in the liquidity bucket to keep clients in their seats when they look at their growth bucket can decrease their long-term success, with neither the advisor nor the client knowing it. For example, if a 50 year old client with $5M tells you they need $2M in cash to "stay in their seats", and that cash has a return of 0%, you're at best getting a 6% return on the $5M over the long-term (and that's assuming a generous 10% for equities in today's world). At 50 with any normal level of spending, that money will not last throughout their lifetime. MPT can help me find ways to have the same level of volatility (or max drawdown), keeping the client in their seat, but also incorporate other asset classes with a greater than 0% return. It can also help me frame a discussion around a portfolio's potential return path using standard deviation, max drawdown, or a number of other measures.
With MPT I have more information, a better discussion, and if I want, an objective methodology to diversify beyond stocks and cash.

As we stated in the article, we believe objective decision making in asset allocation is the key and MPT is one way to do it. You don't have to bring MPT back from the dead if you don't want to, but I would argue it never died in the first place.