About Problem 1, I must stay vague, but the code I read was understandable. We tracked the time it took us to review the artifacts and since this is still an open problem (how to efficiently and fairly review artifacts), the process may change in the future.

To address the potential negative impact on the authors, I believe the papers who did not get a good review by the artifact evaluation committee just did not get a special mention. Since it is not possible to know who submitted an artifact and who did not (unless you got a mention), no harm is done for now.

The potentially negative impact on the authors' reputation was something that concerned me because I've been burned in the past by Ph.D. students not being able to use the tools I published and saying that my tools were buggy when they just did not know how to install Eclipse...

About problem 2, the conference organizers promised to keep the data confidential, but that might not be enough in some cases. For example, I would never show my interview transcripts to anyone, but there are some intermediate data that I could show and describe. We did not need to reproduce everything, we just wanted to see reasonable evidence that the approach described in the paper had been validated as advertised.

I'm not sure I understand the difference between problem 2 and 3. I must say that in my research area, I don't see many approaches and studies that are exclusively about proprietary data. Often, some part of the data/technique is publicly available or the approach has been tried on both proprietary data and open source data.

Overall, I think the artifact evaluation committee is a nice initiative and a step in the right direction. It needs to be carefully monitored and adapted to ensure that nobody gets burned for a bad reason though.