Then your issue isn't with the trade it's with the team as it's constructed - Right or wrong the team isn't made to be this a quick carry the puck in team. They're built as big players that force the play physically and grind you down. Vrana wasn't made for this team as constructed, Mantha is and you proved the point for me with your description of him being a large player. Looking at strictly the way the team is constructed Vrana doesn't fit. Mantha brings the size that the rest of the team has and the ability to play a heavier game. Vrana was nonexistent on the back check, Mantha is not. Vrana couldn't park in front of the net, Mantha can. Vrana is little more than a speedy goal scorer it isn't a knock on him it's just the facts. Add to it that at least 3 coaches had issues with getting him to buy in to the team philosophy and Mantha is the much better fit. You add the kicker of 1st and 2nd round picks as if the fact that the cap dump wasn't there in Panik as well.
Yes, my issue is how the roster is constructed. This trade is part of how the roster was constructed, and is emblematic of the removal of pace from this team.
Not every player has to play the exact same game. In fact, you actively don't want your roster to be 100% the same type of player. You want to be able to synergize, and find combinations that work well together. You need to present the opponent with more than one look, or else they can simply overload to counter your look. You need to have some speed through-out your roster to back guys off. This doesn't mean you aren't playing "heavy hockey." Heavy hockey
benefits from having speed and skill to pair with your mucking players. The speed backs off the opposing D on the rush, and creates space to gain the opposing zone with possession. Having that speed creates options to distribute the puck as you gain the zone, and creates seams to feed the puck back to the weak side of the ice (and getting the puck to the weak side is something that Laviolette absolutely loves). Without that speed thru the neutral zone, you're stuck having to chase the play constantly, and your F3 is caught higher in the zone in defensive positioning as result.
If you don't believe me, maybe you'll be believe Laviolette. Here's a presentation he gave in 2016 about creating offense. He lays out three over-arching offensive attacks, although the later two are basically variations on the same concept (one in which your player gets to the puck first and one in which the opponent gets to the puck first). His first, and preferred option, is to carry it in with speed. He literally says the phrase
"I would love to see the puck with wide speed."
Being physically large doesn't mean you play large. Just like having straight ahead speed doesn't mean you are going to be a good fit on a fast team. Playing fast means you are able to execute plays in stride, and find seams for yourself and other players. Playing large means you have to use your size to create possessions. Mantha is very inconsistent in the usage of his size, both offensively and defensively. He very often plays a small man's game, trying to set up in a scoring area and let his line mates feed him the puck rather than dragging it out of the corner himself.
I want all the "heavy game" advocates to explain what they think a "heavy game" actually means. Not in platitudes about "playing big" or "wearing the opponent down." What's the actual system a heavy game entails? What forechecking scheme? Who do you envision being our F1s, F2s, and F3s under a nominal rush? How do they obtain and maintain puck possession? Who gains the zone and in what fashion? How do they beat a left wing lock? How do they beat a 1-2-2 trap? Give me specifics. Not platitudes or empty rhetoric.
Once you think thru the actual X-Os of playing heavy hockey, you'll quickly see the value of speed to this team.
This isn't some "ohh, look how good our former players are doing" post, so I'm going to ignore that paragraph. Vrana was brought up because he got a new contract, and I expanded on the point I had made previously during discussions of the trade that he wouldn't be more expensive than Mantha (something that supporters of the trade had claimed was a rationale behind the trade).