The answer is, it depends on your investment objectives.
Deliver Uncorrelated Returns
The original objective of introducing alternative funds to a portfolio is to remove or reduce the portfolio's systematic risk or at least include funds with low correlations with stocks and bonds. If the alternative funds you used in your portfolio helped you meet that objective, even the alternative funds' own returns are not particularly attractive, they have fulfilled their missions.
For example, while the long/short equity funds generally move at the same direction as the broader market, their volatility is a lot less than the broader market, as shown in the previous blogpost's chart. Specifically, in the past 5 years, Long/Short Equity funds' average annual return is around 6% (vs. S&P 500's around 14%), in the period where the market was down, for example, in a period when S&P 500 was almost down 20%, the Long/Short Equity funds only down around 6%.
Another example, generally speaking, Managed Futures funds had meager returns over the past 5 years, but in 2008 when S&P 500 fell 37%, a Credit Suisse managed-futures fund rose 23%; in 2011, when the S&P 500 gained 2.1%, that same fund lost 4.9%. Clearly, this fund delivered the uncorrelated performance.
The Bottom Line
You add Alternative funds to your portfolio not to chase their returns, but to reduce your overall portfolio's risks. If this is your objective, then Alternative funds should have a place in your portfolio, but maybe a small portion, like 10%.