I really don't think any of Grier's depth signings are going to block the kids in the next couple of years. They're generally only here for 2-3 years which is a pretty reasonable transition timeline for the 2019-2021 classes. Benning being around for 4 years is probably not going to be a detriment to our extremely shallow defense pool.
I would assume that the 2022-2023 season is going to be a season used to get the kids acclimated to the pro level while the big club is tanking. Some of the kids will probably get cup of coffee call ups this year and Nieto, Bonino, and Viel will come off the books next year.
Then 2023-2024 is probably when the 2019 and 2020 classes will start to establish themselves as NHLers. We'll still probably end up being tank bad. Then by the end of that season, Kunin and Lindblom and Barabanov are done.
I don't exactly see clear cut obstacles for the kids and if things go well. The only real forward pieces that are hard lock obstacles are Couture, Hertl, and Meier. The other 9 spots are generally going to open up as the prospect classes matriculate.
On defense, Ferraro and Karlsson are the only two of a high enough quality to block off prospects and even they're not guaranteed. On top of that, we only really have Merkley threatening to take a spot on defense. Hatakka and Knyazev are still pretty early in their development.
If DW Jr's drafting proves to be good, and McCarthy's development proves to be good, and we end up being tank bad and get an Adam Fantilli next year and a Macklin Celebrini the year after, you could have a young, skilled, talented forward core by the 2024-2025 season.