Slaf always shown a high level of hockey IQ.
But you need hockey IQ to see hockey IQ...
It's quite easy to point at the sky a say it's blue tho
... I don't exactly love the reductive view of hockey IQ, because it can be hard to judge.
Like, what is Hockey IQ? A mix of vision, quick decision making, making good decision on the ice, on-ice awareness, positioning, etc.
When Slaf was a rookie, it was easy to question his hockey IQ because he frequently looked lost on the ice and his decision making was timid. There were flashes, but as fans its hard to know what was lack of experience and/or comfort and what was lack of hockey IQ. We're seeing more displays of good hockey IQ now (although Slaf's rawness is still evident), but its been a development process to work on his skills and comfort in the NHL. This is partially why having a front office that values actual development is important.
Slaf was always known to be a raw prospect, but with his growing comfort to make plays and shoot, its more evident now just how his ceiling could be.