First all, I'd like to say that I like Melovsky. He's a good defensive center who skates well and is not afraid of the greasy areas. He's got decent size and good skates.
But you also need to add that, when taking a double over-aged player in Round 6 you simply need to hope they're not taken in the next handful of picks and you can essentially sign them to a tryout contract for free.
Melovsky was still a better pick than Graham, as he has a good shot at paving his way as a bottom six center in the AHL and an outside chance at a 4th line C role in the NHL. But it's tough to fathom why an NHL braintrust of a team with $100 million dollars paying team and staff can't figure out that they essentially wasted two picks on players they could have just signed, and instead took the two highest upside available guys in the 5th and 6th rounds and wound up with 4 prospects instead of 2.
So ultimately, I'll say it wasn't a *bad* pick because Melovsky should play a role in the organization in some capacity. I like him as a player, he has heart and some sand and defends and skates well. But as good as our Russian scouting has been, I would've preferred the team to roll the dice on a Kol or Krutov, both of whom were taken by Carolina, and then sign Melovsky tomorrow.
I don't think this is strictly true - so sure, you can invite a guy to development camp, or even try to sign him to an AHL deal, but this gives the Devils control over his rights entirely. Chances are that they don't even sign one of these guys to an NHL deal, which, again, I agree that the Graham pick is terrible, but they were not willing to risk A: them being drafted by someone else B: them falling through the draft and then potentially signing with someone else C: having to sign them to ELCs when they may not warrant it. This also gives both guys the option of going back to junior for an overage season without it counting on an NHL contract, which is also nice.
As an example, Ondrej Palat was drafted by Tampa in the 7th round in 2011 as a double overager, with only 4 picks left to go in the draft. They could've let him pass through the draft possibly, and then competed with other teams to sign him. They didn't sign him to an ELC until the end of training camp that year, seeing enough to justify the investment.
I think drafting one of these guys is totally fine, but two is definitely a mistake. That said, I like having a list and sticking to it - yes, you can sign a guy, but there's no guarantees.