I think on a team more cap space and better roster composition, this move isn't bad. Because Brandon Tanev is a useful and somewhat unique player. I know it's really memey to say, but he truly is a heart and soul player that every team in the league would take if asked because what he does have has a ton of value - special speed, buzz-saw tenacity to work corners, totally willing to sacrifice his body to make plays. His offensive toolset and overall hockey IQ are probably below average though, which is why he's been relegated to the bottom six. And there isn't anything wrong with that.
The problem is, Rutherford totally thinks he can be useful in the Top 6. But he's been an offensive black hole and his defensive game I think benefited a ton from Lowry and Copp. And that shows a frightening disconnect from reality for an NHL GM. I think even when Johnson and Gubrandson were acquired, JR understood what they were. He just overvalued them.
Here I worry it's a perfect storm of totally misunderstanding a players use AND value.