I'd rather have a 23 yo Rossi at 7M signed for 7 years than a 28 yo Rantanen at 13-14M signed for 7 years. That extra 7M could get you a nice player. I am not convinced that Rantanen is a guy who can drive play on a 1st line- I'm sure he would do well playing with Kaprizov, but so do a lot of players. The fact that he isn't doing well with Aho, who is a better C than anything we have, is a red flag for me, as are the complaints that the Avs fans had about him before he was traded.
To be perfectly clear, I would not even trade Yurov for him. In a salary cap world, young players performing well on ELC's are a must. You can't load up on a few expensive players and expect to win, as Toronto has proven.