I really don't think that's true for high-level professional players. Sometimes, yes, it's difficult to immediately count exact units compositions. I don't think professional players are getting confused by unit designs or finding it difficult to identify low-health units. (Don't pros play with all health bars on?)

It might be "unfair" for some almost purely number-based confrontation like a phoenix-versus-phoenix battle. But are we really that impressed by testing which human happened to be better at estimating the number of stacked phoenixes? To me, that's not what's interesting about competitive Starcraft 2. I'm more interested in micro, like pulling back injured units, or choices like "it makes sense for me to force us to trade out our phoenixes right now even if I lose the battle."

IMO image recognition in computer game would not be hard to implement and it would be very pricise. So it wouldn't change anything in the end. And image recognition for computer game probably is not very useful. Also your brain is limited by neuron number, your energy source and AFAIK AI does not use those limits either. It might be interesting in a sport sense to compare human and computer which allowed to use only 10 watts of power, for example. But in practice you don't have those limits, so it's more interesting to push the bounds.

I'd love to see how an ML developed vision processing algorithm providing the parsed info would affect performance.