It's always really hard to strike the right balance in dynasty between being too reactive and too rigid. There are four extremes with young talent:
THE DOA BUST - Starts Bad / Ends Bad (ala Laquon Treadwell, Trent Richardson, Royce Freeman)
THE LATER BLOOMER - Starts Bad / Ends Good (ala Roddy White, Jordy Nelson, Thomas Jones)
THE FOOL's GOLD - Starts Good / Ends Bad (ala Sammy Watkins, Chase Claypool, Kareem Hunt)
THE REAL GOLD - Starts Good / Ends Good (ala Marques Colston, Amon-Ra St. Brown, Mark Andrews)
There's no magic formula for always slotting guys into the right bin. Personally, I tend to be skeptical of 2nd year running backs since there's a tendency to overgeneralize decent initial performance into the expectation of enduring success. I'll usually anchor to my initial evaluation more than the winds of the moment, though sometimes it gets me into trouble (see: Trent Richardson). However, I think it's prudent to make exceptions when someone looks exceptional. Sometimes guys flash in such a strong way that their greatness seems undeniable (I'd put the likes of Jefferson, JTaylor, and Stroud here). Problem is that the price tag escalates quickly if you missed the train leaving the station.
On that note, I'm not willing or able to rank the rookies going into year two, but I'd suggest that the obsession with rankings is somewhat misguided anyway. It doesn't really matter who's #1, who's #5, who's #10, etc. A more useful way to frame it is to consider which players are the best buy/sell relative to how you value them vs. how the consensus values them. If you see a "profit margin" between a guy you think is good vs. a generally apathetic general opinion, that may be an opportunity to pounce. Trey McBride would've been one of those for me going into this season. Maybe Alec Pierce is another from that class.
I don't always get those right, but I know if people are cooling on the likes of Pitts (2021 class), Bijan, and JSN then they may become especially attractive buys. On the other hand, if the hype train is getting too crazy around guys like Rice and Nacua then maybe your early riser becomes a sell high candidate. It's more important to hunt those margins than to trouble yourself with devising perfect rankings of every single player.