Power is not the sort of player who wows you with his speed, skill, or physicality, but he also a player who almost always finds a way to affect the play. He is tall, somewhat gangly guy who has yet to grow into his body. I am not worried about his lack of physicality, which is overrated, anyway. If he has a long reach he can get to and cover players easily, and his height will allow him to use leverage on all but the biggest, strongest players. His shot is already an asset. He seems to be a smart player, which, IMO, is critical for Dmen.
It remains to be seen how physical he will end up being. Just a couple of years could see a big body like him put on 25-30 lbs, which will drastically affect his skating and power game. He will never be one of those smallish, shifty, fast offensive Dmen like Makar or Hughes, but that's ok- there is still a place in this game for a big man, let alone a big man who can defend and has an offensive game.
A very high end comparison game would be Larry Robinson. I think he has the offensive game, but don't know that he will ever have the physical game that Robinson had. Big Bird wasn't the most graceful skater, but he got where he wanted to go, and was a great two way Dman. You would hope that Power can do the same.
I will end with this. I have watched a good half dozen of MI's games, because I am fascinated with some of their talent such as Beniers, Johnson, and Bordeleau. Powers disappointed me at first, but the more I watch him, the more I appreciate him. Anyone who drafts him would be wise to plan on keeping him in college or the minors until he has filled out, and has got his body obeying him. It often takes longer with really tall players. Robinson didn't play in the NHL till he was 22. Playing him in the NHL next year would be a disaster in the making.