Yes, this deal is devastating for us Sharks fans from an emotional perspective. And yes, when you look at Vegas' 2-3 contention window based on the age of the roster and cap situation, the Hertl addition looks great so the return leads to a "LOLGrier" response. However...
1) Hertl wanted out and has a full NMC, ie he controls where he goes, and clearly Vegas is a perfect fit for him with that contention window because....
2) Hertl is a 30-year-old great 2-way 2C right now but has undergone at least 4 knee surgeries including two ACL repairs and one that has him IR'd now. If his contract had only 2 more years left on it, this return would be terrible. Those last 3-4 years are going to look a lot worse when he is 33-36 years old. Maybe he'll age like Pavelski (for his sake, I hope so), but given his career so far and the style he plays, I have a hard time seeing it.
3) Retention: this deal was never going to get done without retention given point #2 and those looming last 3-4 years of the deal. Retaining only 8M out of 48M left on his contract is pretty damn good (just like Grier retained only 6M out of the 46M left on Karlsson's deal).
4) Given the NMC, Hertl's age and injury history, and negative value of the contract, getting an unprotected 1st (shit happens during any season, you never know...) and a 1st round prospect projecting to be a middle-6 center is pretty solid
5) Third round picks: this part is weird but honestly who cares? The odds of a 3rd round pick making the NHL is pretty low. The Sharks got one back in the Duclair trade already, and I bet they can get 1-2 back at next year's TDL as well. Not a deal-breaker at all imo
6) Ultimately it helps the Sharks bottom out this year and next year, which is good for their rebuild...gotta hope they can get Macklin Celebrini at the end of this year
7) Yes, it's devastating for us Sharks fans to see him go to Vegas, but seeing him sulk here for another 2-3 years of losing while becoming a negative asset would have been much worse. I wish him the best of luck in Vegas (ugh).
8) Just like with the Pens/Devils deals for Meier and Karlsson, Grier is getting mocked now but long-term, I suspect this deal won't look all that bad. There's no way to win these types of deals in the short run, but given the state of the organization, I think he did just fine with what he had to work with in the salary cap era.