There is some real negative sentiment here, that I understand, but don't at the same time.
Yes, their growth is flattening, they've done some less than honorable things in the past, but if you look at the big picture, they have some great talent (which may or may not be leaving), they really haven't had any prolific product failures or missteps, and they've made a solid name for themselves in the gaming business. (I doubt many of their users or potential users know about the stock option BS or their past with scammy offers)
I'm not saying Zynga is a clear winner, but what I am saying is, they are not a clear loser.
You have a good point but to offer a counterpoint, their many problems probably shine through or will shine through in other unpredictable ways. Its almost like having a friend who has a problem they don't want to talk about - after a while you start to notice some oddities. At the least, I would guess that their reported on behavior will drive away talent from working there and probably as a result the quality and value of their products will suffer.
I'm not saying Zynga is a clear winner, but what I am saying is, they are not a clear loser.