A guy I drafted, Abanikanda, do I really want to hold him until his rookie deal expires? He couldn't have landed in a worst spot, even though I like the talent.
You never know when somebody will get hurt. That's really what you're looking at with Abanikanda, because Breece Hall is going nowhere unless he's hurt. Miller and Kamara might be different in that Kamara is aging (he's twenty-nine) and might lose a step this year, but that's even tenuous. But really, what can you get for Abanikanda if you trade him? You're not getting the third (which is what you likely spent on him) back that you picked him with. So he's probably worth a hold when all is said and done, unless you see a guy in this year's fourth with a clear path to playing time or something like that.
Your broader point about drafting guys in FF hoping somebody moves on is one to think about. These guys are getting one contract and done or they're having to pull teeth in the front offices to get a vet contract. You need a guy who makes use of and produces during that first contract. Situation is important to look at when drafting RBs, therefore, if you ask me.