'tFirst off our system doesn't require high hockey IQ. Second and more to the point during a rebuild/transition years you shouldn't actually adapt your system to match the players you have because the players you have because the players you have are going to be changing quite a bit over the next few years.
Our system right now is pretty much man-to-man, with a mix of zone defense, and we're running the 1-2-2 that most teams similarly do, sprinkled-in with some amount of neutral zone pressure and whatnot. It's not rocket science.
But the way we set defensive attributions, and the lack of clarity when it comes to it all since what St. Louis advocates for (or at least did before this year) is basically a type of "position-less" hockey most prevalent in the NCAA, with some limitations suited to the NHL games (a focus on center responsibility).
All of which means that players need to make reads on the fly a lot of the times instead of having more specific roles to play on the ice.
The trade-off here is that if everybody is up to speed, then we have more flexibility both offensively and defensively since our F1s, F2s, and F3s can change on the fly and our D can permutate as well. This frees-up a lot of ice to produce offense and many variations that lead to increasing scoring.
Inversely, since adapting requires reading the play at all times, it also adds a time variable to the processing of the game for our players. Meaning that if they aren't able to react very quickly (aforementioned high requirement on hockey sense) then they actually lose tempo vs. a simpler, slightly more rigid and less flexible gameplan.
So yeah, St. Louis' system actually definitely requires more out of our players when it comes to hockey sense vs. what is most common in the NHL right now.
That system works in the NCAA, and might eventually make it to the NHL as more than the "side concept" that it is now, but that time hasn't come yet given how structured of a game eventual Stanley-Cup winners have been playing basically since the end of the 1980s.
Then comes the second part of your post.
And frankly I kind of agree in a sense. Since we're shooting for an effective gameplan once our personnel turnover is done there's no need to "cater" to our existing players per se and we should instead try to institute the gameplan that will be most conducive to wins when our roster is eventually deep and strong enough to actually contend.
But then again, the mark of a good coach is to be able to win no matter the circumstances and get the best out of his team. You don't need to adapt the system that much to the roster if you can just do some small tweaks and be "good to go".
That very inflexibility (or unwillingness to change) in strategy is one of the factors that actually characterize bad coaches from good ones.
And also, ask the Oilers, the Sabres, and other such teams' fans how much losing their focus on winning has cost them in the long term, and how much longer their rebuilds have had to be because of it.
At the end of the day you need to eventually right the ship and start going, or you get stuck in the mud, lose traction, and have to do it all over again. And that requires winning some hockey games, which requires both better personnel, but also at least competent coaching.
