Excactly. Their drafting from first round (outside of maybe the last three years, and everyone of those guys are still magic beans) has been nothing spectacular from 2001. And you rarely get close to NHL-ready players after the first round.
Prospects making the team and having an impact +1 year from their draft is nothing out of ordinary. There are plenty of players who would have made an impact in Detroit's team and who were +1 year from their draft and who haven't been top-picks. From 2011 Couturier, from 2012 Hertl, Girgensons, from 2013 Horvat, Nichushkin, Lazar, Wennberg and Burakovsky. Those were just on the top of my head. None of them hardly is described as "franchise" and Larkin really isn't (yet) anything more special than any of them.
All this being said, Larkin is a very good prospect. At this point he seems like a guy who should have been taken earlier in the draft, but things might change. In many ways he reminds me a lot about Girgensons (after about 2 years after the draft he seemed better pick than F.Forsberg. Not sure anymore
), who almost every Sabres fan and the management loves. They have similar strenghts and weaknesses as well.
But this talk about being a franchise guy that Buffalo would maybe now take instead of Reinhart is just getting really silly (and it really is a disfavor for Larkin himself, to be honest). I understand the excitement of having a surprisingly NHL-ready prospect in a long, long time. But it really isn't anything THAT special, when you have a little wider perspective league wise.
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And there really isn't anything to lose in giving him a spot at this moment. You have players (at least D) on IR and the worst casualty would be putting a stud like Cleary or Andersson to pressbox/waivers. If Larkin seems like needing some time in AHL, you can easily put him there anytime you want.