I really haven't been too involved with the "1st or 2nd overall" discussion as far as Kakko is concerned. I've always, even from the last season (17-18) thought he might turn out as great as you'd expect from someone heading first to the podium. Also I'm aware of Hughes having a great year (even though the production haven't exactly upped from last season) and we're dealing with someone who's been touted to go 1st overall for some years now so obviously there's plenty of preconception as far as the discussion is concerned. At the end of the day, like others have pointed out the draft # (at least when dealing with lets say top 1 or top 3 picks) doesn't really even make any difference, aside from perhaps the media circus. Not that it wouldn't be kewl to have the first even Finnish first overall pick, but there's plenty of time for that.
Anyway, there's couple of things that work in Kakko's favour here, such as: i) having no physical question marks (great size and pretty great skater already) ii) not only playing against grown ups, but proven track-record of already having the game breaking ability at pro level iii) production, while it's nearly impossible to get to PPG in today's FEL and there are just couple every year who can do that, Kakko still has the chance to accomplish the unprecedented and break this barrier and so far has been scoring points at extremely high rate iv) position - not only does he have every trait you look for in a nr one center, it is clear he's already being molded into one v) comparable prospect like Laine, Barkov and Rantanen - who is the producwhere the l is a product of the same organization - Kakko is looking quite a lot better than him at the same age (I watched all of them closely) while producing at higher rate than Laine did (although he had less ideal circumstances). Barkov currently owns the record for most regular season points from D eligible prospects and should be involved in the discussion as Kakko does play both positions. Of course we need to keep in mind that the development isn't linear. So lets say the lottery winner got to pick Rantanen or Hughes/Kakko in the draft, there's no way either one of the two would stand a chance. Nonetheless Kakko looking better than Rantanen in their respective D seasons absolutely has to baffle and raise discussion amongst a lot of scouts as we speak.
In the last game for the TPS he played first full game as a center in FEL without any elite level wingers (talking by league standards), he immediately scored two goals and was instrumental key in the win against HPK. Aside from the goals Kakko could have added punch of assists from the quality high end scoring chances he created. I don't see why TPS would suddenly move him back to wing after having last game like that and they clearly already see him as a future C and there's nothing indicating Kakko not sharing the same aspiration. He may play wing at the World Juniors but mostly because of the logjam in the middle.
Now as for stylistic comparisons, he looks like young Forsberg out there who isn't afraid to get into the traffic/boards, has shown some mean streak by for instance occasionally bulldozing defenders to force his way while having unbelievably smooth hands, agility and core strength, which enable him to steer through tight places and control the flow of the offence. Of course like any other 17 year old he isn't yet perfect and has to work especially on the defensive aspects of the game. While I think he's already a great skater, he's going to be a whole a lot faster as he develops and if a grown up defender cannot contain him at 1 on 1 right now, they'll have a heck of a lot more to worry in the future. Anyway, P. Forsberg was the first player that comes to mind when I try figure out any past examples. I'm thrilled to see how fast Kakko can adapt playing at the smaller rink in the WJC and what he can accomplish there. Let the games begin!