I have written 2 previous posts on the shortcoming of robo advisors. Probably the most important is that they know virtually nothing about you before they determine your portfolio, They are not set up to take account of your tax situation which is crucially important as well as many other factors related to personal circumstances. For instane what if a family plans to have additional children or an investor plans to make a radical career change such as leaving a job with a steady salary to start their own business ? It doesn't take much thought to imagine the many,many other factors that could be added to the list.
A comparison table of robo advisors below.lists the following as inputs uesed to determine a portfolio allocation:
Future Advisor: 2 factors: age and risk tolerance
Wealthfront 10 question financial questionaire
Wisebanyan questionaire risk score