Honestly, I'm in no way that worried about losing the four 1st round picks. Players like this are normally considered untouchable. Teams won't even consider trading them under most circumstances. He's a 21 year old coming off a near 100 point season, with the kind of game that warrants every reason to believe he'll continue to improve as a player.
We have a good amount of prospects, young players, two 1st overall picks, one of which potentially generational, an absolute stud D prospect about to make the team, then you add a 22 year old superstar in Marner, and Ray would recoup at least one or two firsts over the span of 5 years, guaranteed. Even if by just trading up from the 2nd. JT Miller just fetched a 1st. We would only go at most 2 years at a time without a first anyway.
Our scouting staff has given us plenty of reason to believe they can find talent in the later rounds too.
If we're heading toward win now mode there's every reason to believe we may go 2, 3, or more consecutive years without a 1st like most other teams if Ray starts trading them at the deadline. Give me a 22 year old superstar over whatever overpriced rentals that end up not fitting in and leaving that those 1st rounders would be traded for, every day of the week.
For me, the money element of this is the only debatable part, but a salary cap that could very likely be approaching $90M or more in the next few years needs to be at least kept in mind while having that debate.