Expanding on that second one, if the most reliable way to get promoted is to create something of value to the company, that's a very good sign. If the main way to get promoted is for your boss to like you or owe you a favor, run away.
(I don't see any of this as a problem, BTW, but I think it's worth pointing out.)
Selling all your stock comp immediately is more about diversification of risk.
If rsus are a nontrivial aspect of your comp, then you're already extremely exposed to risk in your company's stock price stock price (if it tanks take a big pay cut and they might even lose their job).
So, rather than gamble, I did what I felt was prudent and sold all my stock. I've got plenty tied up in the well-being of the company already, from my unvested stock to my future career trajectory. Even the value of the real estate I own could rise or fall with the fortunes of my employer. I don't need my fate any more tied to or correlated with the company than it already is.