Somehow, the changes announced in this Notice are supposed to help postdocs make a "more timely" transition to independence.
I think the main problem will be that reviewers are already largely biased with the mindset that a certain publication profile is necessary to make someone competitive. Meaning a certain number of papers in a certain "level" of journal. In order for the timing of this process to work, postdocs will need to start applying for the K99 in about year 2, by which time it is very unlikely that anyone but the ultra super productive (which is often aided by the good fortune of having a PI who lets you choose quick-to-paper projects over those that they might WANT you to be working on), or those in big-name labs, will have such a profile. Since reviewers won't have as lengthy of a publication record to go by, they will almost surely fall into the habit they do for every other kind of NIH grant and go instead on other aspects of the CV (and the CV of the mentor), further pushing this towards a "glamour" award. The "rich get richer" situation will be exacerbated, in contrast to what I have always seen as an advantage of the K99 award (that even the not as "fancy"--like myself in a lot of ways, lol--can have a fighting chance).
Also, year 2 is when a lot of people become most competitive for the F32, so it might become a choice between F32 or K99, which seems kind of stupid. Is F32 going to end up as some kind of consolation prize for not being fancy enough for a K99?
Not only that, but this will disproportionately disadvantage women (and men who are primary or co-primary caregivers) who have children during their postdoc years. So far, the longest extension on K99 eligibility that I have heard of anyone getting for family leave is the actual number of weeks/months they were out on parental leave. Anyone who has had a kid knows that the effect on your productivity goes FAR beyond those few weeks/months. If they want to avoid this kind of bias, they will need to get real about extension times--people should get at least a year per kid, just like in the tenure clock stoppage situation.
Lastly, I think it is paternalistic and invasive for Program to be making judgements about someone's need for a K99 award and readiness for the tenure track based on their job application timelines. A large proportion of postdocs go out on the job market before they are truly ready because their PI won't or can't pay them anymore. Making that the postdoc's FAULT by now also telling them they are no longer eligible for one of the best options to win their independence from that PI is just gross and unhelpful. This treats postdocs like they are little kids who say they want dessert now even though they didn't eat their vegetables: "Well then, you must not need any dessert because you must not be hungry." Well, guess what: your reviewers are scoring highest the people who already look ready for an independent position. So you're going to have to figure out how to get them to change their mindsets--something that so far, nobody has figured out how to do very effectively. How is that going to be reconciled with the new rule that:
"Individuals who are close to achieving an independent faculty position, and cannot make a strong case for needing a minimum of 12 months of additional mentored training, are not ideal candidates for this award"?
I wonder if they have even thought about this. I also wonder if these changes are based on any actual metrics about applicants and awardees, or just some vague, poorly thought-out knee jerk idea to make postdoc-hood shorter. If you can show me Jeremy Berg-style data demonstrating that there will be some benefit to candidates, fine--but it just doesn't look like this is going to be a good thing.