I think the Armia example shows the opposite, personally... Unless you think Armia doing well in the AHL will translate to him finally bringing a consistent game to the NHL
For an athlete with the skill & physical talent Armia possesses, not unlike Slaf, it's easy to excel at the lesser pace of the A... And, easier to do so without the same attention to detail.
For Slaf, playing there very likely would lead to big production, but any confidence gains could also offset by developing bad habits because of what he can get away with thanks to his unique tool set.
He seems to be playing with increased confidence & effectiveness at the NHL level. I see zero value in sending him to a lesser league at this point.
As Axl said, "All we need is just a little patience"
Future is bright