He's 6'4 (close to 6'5), can skate, great dressing room guy / leader, right hand center and pass first guy. Can be a prick on the ice at times, but not enough in my opinion. Not an overly physical guy for his size, but uses his body very well and has a good active stick. Very good defensively. In junior he played all situations, PP/PK/ES. With Chicago he played "behind" Dylan Strome & Jonathon Toews, both whom average over 17 minutes of ice-time, but surprisingly Dach came in around 18 minutes with virtually NO PP time, yet scored 26 points (Compared to 48 for Strome & 37 for Toews). The year before Dach had 10 points in 18 games.
He's only 21 as well. I don't get the Kotkaniemi comparisons as other than age they are two very different players. In his first three seasons in Montreal, KK played extremely sheltered minutes (around 13-14 a game), Dach has not and was Chicago's most used center last year.
Dach is also a more cerebral player than KK, and already has the defensive game to keep playing higher minutes. The difference in Montreal is that he'll be doing so with actual scoring wingers now / top 6 minutes and no need to be protected on the ice, either physically or defensively like KK was.
I think if you give the guy until Christmas, many opinions will be changed watching this guy day to day. I think Montreal could use a 21 year old, huge right shot center with a great makeup / leadership who chips in 40-50 points a year and can play in all situations behind Suzuki.
Time will tell.