I can't believe I am going to get into this but....Ok, by what objective measure are you saying he is better than Tarasenko? Is this based solely on the 12 games? Because if you take Nylander's entire NHL career (which is still a tiny sample size), he has posted a very respectable .73 ppg. However, that is just a 60 point pace. Tarasenko is a multiple 70+ point scorer who has a career .81 ppg playing with a MUCH worse center than Matthews (Lehtera). Are you going just off this year? Its most likely unsustainable. Nylander has just 4 points 5v5. His powerplay production is nice, but not sustainable as the PP point leader last year (Kane) only had 30.
I get that Nylander is new and shiny. I get that he has played well and looked exciting. I get Toronto hasn't had much to cheer about for awhile. But Nylander has much to prove before he is hands-down better than a multiple 70 point, 40g player in his prime. He might get there, but its no sure bet right now.
That's just Tarasenko. Pietrangelo > Tarasenko, at least imo, in terms of importance to the Blues. We are not a playoff team if we trade Pietro for Nylander. That's not a knock on Nylander as he would be of great help. Petro is just too important. He is quietly excellent playing the most and toughest minutes for the Blues. He solidifies our D core. Shatty is a great PP QB. Parayko is an excellent young top 4. But neither could carry half the load Pietrangelo does half as well. He allows them to be ins situations where they can succeed.