It's hard to bring up Tatar and Nyquist in a positive light after these last few playoffs. They're old enough now where I wanted to see them take the bull by the horns. Instead, all I saw is that we're in trouble when Datsyuk and Zetterberg retire. Of course, I may be wrong, but you're not right either. We haven't yet seen that these two players are top tier players that can carry us in big moments. They need a star player around them, like a Datsyuk, Giroux, Crosby type for them to excel. Even then they haven't done so in the last two playoffs with Datsyuk and Zetterberg. To me, they look like followers and not leaders.
Dekeyser is a defensive defenseman that can be a top 4 guy. He's not a GR player that people have raved about, because his background had nothing to do with GR. I was talking about Smith and not Dekeyser.
While I don't disagree with your logic, I will say this. Tatar and Nyquist have outperformed Datsyuk and Zetterberg (both regular season and playoffs) at similar points in their careers. Dats and Z weren't very good in the playoffs at all during their first few years. And they were about the same ages when they came into the league (arguably both with MORE experience than Nyquist or Tats).
I agree, there's nothing to guarantee that either of these guys will be stars. But based on the information we have, and observation and comparison to our last two stars, I don't think it's out of the question either. At the very least it's premature to think these two guys are don't improving given their respective ages and experience levels. Consistent 65-70 point seasons is not out of the question for either of them. Which isn't super star talent, but isn't anything to scoff at either.