It depends on the opposing team though. If you’re dealing with Pittsburgh for the Marino example, then Formenton is likely more valuable to them than Greig as a team that has a very limited window and aging core.
Also, from the way Dorion was talking about the logjam at centre when White was bought out, it seems like the org also sees Greig as a centre even at the NHL level. So I’d say on that note, it would be pretty valuable to have Greig play LW and be able to shift him to centre when we have injuries to Pinto, Stützle or Norris. Formenton can’t do that. And lastly, Greig is going to be cheaper than Formenton while on an ELC.
I’d trade Joseph over Formenton but he plays RW which is not a strong position for us, and I doubt he has the same trade value.
We have a ton of organizational depth at LW so if you’re dealing from a position of strength, I can see why Formenton would go. But I certainly wouldn’t trade him for the sake of moving him, would only do it for a solid top 4 RD because we badly need one and they are so tough to acquire.