For an 18-year old in Liiga playing on the 4th line and mostly less than 10 minutes a game, Koivu's stats so far are impressive.
He has 5 pts (1G, 4A) in 14 GP.
Out of the 14 games, he played less than 10 minutes in 9 of them. He played between 10 and 12 minutes in 3 of them. And in only 2 did he play more than 12 minutes (12:17 one game and 14:36 the other).
Comparing him to Kapanen, who in his D+1 year played 18 Liiga games and had 4 pts (1G, 3A). Also in his D+1 year, Kapanen played 11 U20 games and 8 Mestis games.
It's not guaranteed that Koivu will be in Liiga all year. He already played one U20 game. And like Kapanen was, Koivu might get loaned to a team in Mestis. Things can change throughout the season. But I think it is still impressive that Koivu is able to put up some points as an 18-year old depth player.
Hopefully like Kapanen did, Koivu will rise through the ranks from year to year and you see clear progress.