Do the devs get feedback from the alpha players? Or are they just watching the big picture to make sure everything works?
Both. Generally most of the visible fixes in the alpha/beta stage are for serious crashes and stability bugs, but they have occasionally taken on balance feedback and other ideas as well at that stage (some recent ones: pricing changes for Fleet Carriers ; making core gems exist to mine at all) where it's been easy for them to incorporate.
They're also aware (or should be by now!) that the way people play the pre-release ones isn't that much like they play the actual released game, especially not after a few months for people to actually learn and share what works. This can go both ways:
- the original engineering they didn't spot that there were some serious balance problems, because they didn't show up in Beta
- the revised engineering in 3.0 they stuck to their plans on certain issues, recognising that the balance issues people were reporting in Beta were a consequence of it being Beta and would disappear naturally after a couple of months of real play (which on this occasion they did: people still have big complaints about engineering, but not about those bits of it)
So more interesting may be what they do with the feedback they get 3-6 months after the live release.