To me it makes absolutely no sense to trade a 23 year-old that is on pace to put up 45 points in his first full NHL season, especially when he's arguably the best play-making winger in your entire organization.
Defense and grit isn't obviously a part of his game, but that doesn't mean he isn't a useful player. Not every player on your roster needs to be a grinder, and he can still work on the details of his game overtime.
Unless we're getting a player with similar potential in return (or he's a part of a package for a more significant player) I don't really see the point here.
The problem is he isn't really producing outside of his hot streak for a couple of weeks. I'm not looking at possession numbers but he doesn't seem to be pushing the the play forward anymore and is often the reason plays are dying or the puck is going back the other way. The special teams have been working pretty decently and with very good goaltending from Markstrom the team has managed to get leads. What hasn't really been working is the 5-on-5 play and the play of guys like Goldobin is a big reason for that.
Not every player needs to be a grinder. But every player DOES need to play passable defense. Even high scoring superstars don't get a pass on defensive play...a 40 point guy definitely won't. The stars may get some extra leeway but ultimately they will need to contribute at both ends of the ice.
But then i don't really see the "potential". I see a guy who has offensive talent but is unlikely to reach a significant level of play because he won't stay in the lineup as he lacks the drive/desire/ability to clean up the defensive and puck possession sides of his game. If I had to guess this is also exactly why the Sharks were willing to move him despite good AHL numbers.
edit: I'll add that you also have a team that from ownership down will be pressing to make the playoffs whether you or I think that's the smart move. As such, if the coach feels he can not win games with Goldobin in the lineup or that he feels that someone else will help him more than he won't be used. More to the point if he gets moved to another team, at 24 years of age at the beginning of next season he will be highly susceptible to losing his spot to the 19/20 year prospect who does things nearly as well as him.