Dumb idea for Dallas. Klingberg produces close to the amount that Karlsson does, has one of the greatest contracts in the NHL, and Dallas could get JVR as an UFA in the offseason. There's no point for them to do that, since they are also losing a number of valuable assets here for little or no improvement whatsoever. Besides, acquiring Karlsson would make it extremely hard to keep both him and Seguin in the team in the 2019-2020 season.

Well, they could get JVR in free agency but they would have to get in line like everyone else, with this it's a guarantee, and karlsson is just slightly better than klingberg but karlsson is the best offensive d in the world and i think it sends a message to the team. Not to mention they would have 40 million to work with to sign Karlsson and Seguin and 9 other players so roughly 20 million to sign 9 players, if you remove hanzal that's roughly 25 million to sign 10 players, except u have young players that could step in on the cheap and probably fill your entire 4th line and 3rd pairing. Not saying it's perfect btw just think it could work.

I agree the Stars do not need Karlsson. I like ur thought, but u need to pick a different 3rd team and Toronto needs to be the ones who end up with Karlsson.

Sometimes it's not about a need, sometimes it's about changing things up enough and bringing in new talent to change the atmosphere, JVR brings a dedication to his body that not many in the NHL can rival. Karlsson is a game changer, Klingberg is great don't get me wrong but if you can get a game changer for a fair deal plus a 30 goalscorer who is a big net front presence and a powerplay specialist i think you do it. All you have to pay for an upgrade on d and a 30 goal scorer is a 1rst, a solid prospect, and get to dump salary, I have no doubt in my mind that any gm in the league would do that.

I also say no.

Klingberg is two years younger, on a super amazing contract (4 more years at $4.25M vs 1 more year at $6.5M), and has always improved with each passing year. If u really want to get technical Klingberg had more points this year than Karlsson (67 to 62).
JVR is a FA and while yes you would have to "get in line" he isn't the only good winger available. He may be the most desired and all but let's not forget that guys like Perron (66 pts), Vanek (24 goals and 56 pts), Evander Kane (should he not sign with SJ he's a 30 goal scorer easily in Dallas), Neal (consistent 20+ goal scorer who has hit 30 before), Grabner (27 goals this season). All in all, I'm not trading Klingberg and Spezza to get an FA that still might not even sign with Dallas and there is no reason to.
In the end, a three-way trade that sees us getting JVR and Karlsson but losing Klingberg, Spezza Gurianov (a prospect that I think will turn out great once he gets comfortable with North American hockey; He showed huge leaps of improvement throughout the season in the AHL), and a 2019 1st is way too much.

Perron and Neal will re-sign with Vegas, Vanek is 34 and will start to get slower and score less, Evander Kane is a toxic teammate, grabner might be the only player here who i would suggest they sign, but as a compliment to JVR on the second line, he could probably be signed around 4 mill. Also Spezza had 26 points last year in 78 games, Dallas needs to dump his salary so they can make some impactful moves this offseason which they desperately need.

http://www.nhl.com/stats/player?report=skaterscoring&reportType=season&seasonFrom=20172018&seasonTo=20172018&gameType=2&filter=gamesPlayed,gte,1&sort=goalsPer60Minutes

Only 2 full time players last season beat JVR in Goals per 60. Laine and Matthews.

Fine, let's suppose that your assumptions are correct (Perron and Neal go back, Vanek slows down, Kane is a toxic player (though some players have proven the media wrong), and Grabner is the only decent player. That right there is enough for me to avoid this whole dump of a trade and go after someone who won't cost me my roster of now and the future.
Also, Stars fans know that Spezza's deal needs to go, there are other ways of losing that contract (Buyout, minor trade with a team that needs a C for a 4th or 5th rd pick)
Lastly, there are other players in the Stars lineup that you did not include that can score goals.

So improving your defense and getting one of the best goal scorers in the league who does it all in front of the net, one of the hardest places to score consistently in the NHL, for a salary dump, the player you are literally upgrading (sure he's on a great contract), a 1rst and a solid prospect. Sounds fair to me.

And yet no one agrees with you. Like others have said Klingberg is producing at around the same rate has Karlsson (so no upgrade here) and JVR can be signed at a later date without losing anything. Good thing this is only fantasy