I prefer to think of it as anything existing at least partly in mind

That's problematic, first, because it leaves mind itself in a strange position. And second because, if mathematical platonism (for example) were true, then there would exist abstract objects that are mind-independent.

We're taking some essential properties we pattern match in science as it is, and then we abstract them, and then we apply them by pattern matching.

You seem to be assuming the pattern-matching of this sort is a vice. If it's useful to mark the pattern in question, and we recognize that we're doing so for utilitarian reasons and not because there's a transcendent Essence of Scienceyness, then the pattern-matching is benign. It's how humans think, and we can't become completely inhuman if our goal is to take the rest of mankind with us into the future. Not yet, anyway.

Religions are also feedback loops. The more I believe, the more my belief gets confirmed. Remarkable! The primary problem with this ultra-attenuated notion of what we want is that all the work is being done by the black-box normative terms like 'improvement' and 'better' and 'optimal.' Everything we're actually trying to concretely teach is hidden behind those words.

We also need more content than 'working with a feedback loop from reality'; that kind of metaphorical talk might fly on LessWrong, but it's really a summary of some implicit intuitions we already share, not instruction we could in those words convey to someone who doesn't already see what we're getting at. After all, everything exists in a back-and-forth with reality, and everything is for that matter part of reality. Perhaps my formulations of what we want are too concrete; but yours are certainly too abstract and underdetermined.