I don't think we should trade for ROR (at least not while we have Eller.. maybe in the offseason), but ROR is not a 3C. He might be a 3C here by pure virtue of having Strome and PLD, but he would be a 2C on many (if not most) NHL teams and could probably be a fill in 1C on a team with weak center depth and/or injuries. Even on a very low-scoring Nashville team, ROR is on pace for 20+ goals and 50 points.
On a semi-related note, trading Lapierre before next season makes a ton of sense if the organization does not view him as a full-time NHLer in 25-26. Being in the AHL this year is disappointing but not unheard of. But if he's not on the team and contributing next year, his value is going to tank considerably (much more than it has).
Also, I agree completely with Wodka that Lappy was so good last year (arguably our second best forward in the playoffs after Wilson), but we're looking at nearly a full year of 'meh' level play. Was last year an anomaly? I would feel more confident in Lappy bouncing back if his D+2 and D+3 years were stronger or if he was dominating in Hershey (rather than playing at a mediocre level).