> I just can't help but feel that nothing AI does will ever be good enough
It can be good enough in a certain problem space, such as chess. But unlike chess or go, which are purely mental games, Starcraft has large physical component (vision, APM, reaction time). It can make it hard to determine when it has “mastered” this RTS. Like you said, it may be a few more months (years?) before AlphaStar can master Starcraft on “mental” level. The physical component is trivial for a computer, so mastering that is not much of a milestone.
Depending on how you define Chess, seeing the pieces and physically moving them is part of it as well. Chess-playing AIs haven't been required to have robot components because that's not the interesting part of the challenge of Chess. I'd argue the same is true of StarCraft, even more so, given that it's an innately computer-based game in a way that Chess is not. It seems arbitrary to require the presence of an electronic-to-physical bridge in the form of a robot only to then operate physical-to-electronic bridges in the form of a keyboard and mouse. Just let it run via the input devices directly. Give it some years and humans will be able to do this too.
In other words, this isn't an interesting handicap to apply.
> It seems arbitrary to require the presence of an electronic-to-physical bridge in the form of a robot only to then operate physical-to-electronic bridges in the form of a keyboard and mouse.
It's not at all arbitrary. SC2 match is won by a combination of reflexes and physical quickness with which the actions are executed, and strategy.
The whole point is to even the playing field in the area of the physical limitations so that only the strategy part is the difference. You know, the "Artificial INTELLIGENCE" part?
It can be good enough in a certain problem space, such as chess. But unlike chess or go, which are purely mental games, Starcraft has large physical component (vision, APM, reaction time). It can make it hard to determine when it has “mastered” this RTS. Like you said, it may be a few more months (years?) before AlphaStar can master Starcraft on “mental” level. The physical component is trivial for a computer, so mastering that is not much of a milestone.