I skimmed it, it seems a bit suspect, holding up as evidence that four relatively recent tech IPOs have dropped since their debut, and the original research was conducted by what sounds like a shareholder advocacy group. Zynga, Facebook, and Groupon didn't drop because of the share structure, and it's disingenuous to suggest that that was a probable reason.
I've seen the damage that focus on short term share price wreaks on companies in the long run - it's paralyzing, as they're forced to focus on the wrong things. Activist shareholders seem to focus on short term returns. Not being subject to that, and being able to focus on long term initiatives seems very beneficial for long term shareholder value as long as you have a good leader.
But that good leader caveat is a big one. Multiple share classes might be correlated with having a bad leader.