Definitely agree with this but the knock on Hagelin is that he doesn't have great puck skills and he can't finish - which is also consistent with how he has played.
That said, I think he's a net positive on the third line. Between Connolly and Eller, that line doesn't lack the ability to shoot the puck. Him being a hound rounds them out nicely.
And adding Burakovsky does elevate the fourth line's ability to put the puck in the net so I think it's just all around good for the team (not to mention Hagelin improving the PK).