I'm not sure why DD is so down on Achonwa. From what I've seen of her (Big East Tourney) and the Olympics, she had moments of looking really good and moments of looking a bit lost. I don't see any reason why she can't stay on the court for 25-30 minutes per game.
Would she always be effective? Probably not. In a way it would be like if we didn't have Dolson. Stokes would have to play 30 minutes per game unless we wanted to go with Buck. Still, imagine if we only had Buck. Say she was in for 30 minutes a game. she'd either get it, or not. I see Achonwa a bit like that (Buck or Stokes - probably closer to Stokes skill-wise).
They will need her to play the minutes and I think she will be up to the challenge. As I said, from what I"ve seen, I like her game and think she's solid.
If you are trying to find reasons why you think ND could hang with UCONN (the generic "you"), then Achonwa would not be a reason. She's not as good as Dolson and I think Stokes could handle her too. But in general, I think Natalie will be solid for them.