The concern with his size has nothing to do with throwing hits. It has everything to do with being too weak to keep forwards boxed out, fight for loose pucks in the crease, board battles and close outs where he needs to be sturdy enough to push attacking forwards to the boards without getting run over. Every small dman you listed is bigger, stronger and faster than Hutson to varying degrees. Each one of them are also much better back skaters.
Hutson is a good prospect but he is very unique and is currently a whole different type of small than any dman that has made it in the NHL in decades.
As for Seattle, the consensus was that they had a great 2nd round with Firkus, Nyman and Goyette. I can't speak to Kokko as he is a goaltender but to arbitrarily dismiss the other three in favour of Hutson seems to be a hyper-biased comparison.
I agree with your last paragraph as the kid is a fierce competitor but we should treat him as a very unique prospect with a unique development curve as he is very dissimilar in too many ways from the dmen that you mentioned.
Give him some time, he will work on his flaws and he have time to work on that before the next step! He will not be a perfect player but he will learn with time how to positioning himself, how to make his stick more effective and his hockey sense will do the rest to compensate his size!
Quinn Hughes have only 1 hit in 17 games this year but he have some flaws in the defensive zone but they play him too much close to 25 minutes a night and they didn't really use it the right way to maximize his strength; they expose him too much but they have nothing else ...
He will never boxed out anyone or win the majority of his puck battle but he will find a way to be effective in a other way. The time of Sheldon Souray and Derian Hatcher who can broke his stick in throwing forecheck in the crease are memory of the past. In the new NHL you can't really use you physics at your advantage like before and you need to play the puck a lot more than before because you can't touch anyone without drawing a penalty.
I understand is pretty unique for a defenseman to have his package, maybe the first, and is really weak at the time but I simply don't see why the size can't stop him to make the next step! We are not talking about d*ck size where a inch can make all the difference in the world but a human body. Hutson have 68 or 69 inches tall and the others have 70 or 71. Some people talk about him like if is 3'8" and 82 lb ... He will keep growing and I think if someone know they need to work on his strength before the next level is Hutson himself!
I have never doubt that Caufield can make it, I know being a forward is a different world to be a midget defenseman but this guy are simply to good with the puck to didn't make the cut! Remember at the time of the big 3, Savard and Robinson are more all around player and Lapointe is the offensive gifted d-man without having the same role of the 2 others at 5on5 but they need him to be that sucessful. I think Hutson can bring the same thing in a lesser extent to his team in using him for is offensive strength and be a nice asset if you use him the right way!
I don't dislike the players the Kraken have taken, I really like Furkus at the time and be happy if you choose him with the 33 pick and Goyette at the rank they draft him it's a good pick but with 4 picks they need to try a guy who can be a homerun and it's more true than ever when is Vince Dunn or Justin Schultz are use to be your PP QB ...