All this talk about him being "best pure defensive player in the draft" is based on what exactly? MHL is not an indicator for this kind of claim at all. Based on what exactly he is better defensively than let say Wilander or Reinbacher?
Simashev is a raw prospect with good tools. That's it, he is a project. All the talk of "Eraser" is pure speculation
Ps Where have you guys even watched him that much?
I'd say that Simashev's decision-making defensively is a tiny bit quicker and overall more stable than those two guys as things stand now. At least it appeared to me that way when I watched Simashev some.
As for a more specific defensive tools comparison, I'd argue that Simashev's gap control and passing lane anticipation/blocking would trump the others' while he is better at exiting the zone defensively and staving-off forward pressure than Willander currently is (and roughly equal to Reinbacher).
I also think Simashev has the best backwards skating ability of those (those back cross-overs of his are a thing of beauty).
Against the cycle I'd say that Willander is probably the better of the three, and the best skater of the bunch in straight lines by the tiniest of margins. Reinbacher's game is more mature offensively, he has the best agility, balance, the better set of hands, and greater transition ability out of the three (Simashev wouldn't be far behind though).
And Reinbacher's shooting ability would also be marginally better than the other two. Although none have much more than average shots by NHL defensemen standards as things currently stand.
If you made me pick, I'd say Simashev has the worst arsenal of shots out of the three of them (not by much though), but inversely he is also the best of the three at getting his shots through defenders' checks/sticks.
Now, if we put comparisons aside and focus on evaluating Simashev's game on its own, then I'd have to admit that I agree with some of your assessment, but not all.
Simashev does have some amount of flaws as a prospect that could mean he never ends up becoming a star, or even true top 4 defenseman. He is pretty safe to be a good defenseman, and projects well overall, but there is still risk he busts therein as opposed to a guy like Reinbacher, who is more polished at this point and thus more likely to reach his potential.
In my viewings, I've found Simashev to still be quite a bit "raw", as you've said, with the puck on his stick in the offensive zone at the KHL level, and it should realistically take him a couple seasons before he works-out some of the kinks in his game. In addition, Simashev will need to work on his shot (slap shot has to get faster/heavier, wrist shot release needs to get better), gain some more physical maturity (200 pounds or so at 6'4 means he could put up another 15-25 pounds no problem) as well as adjust the timing of his pinches along the boards.
He could similarly stand to make his first couple steps more explosive and work on his skating mechanics a bit (edges, ankle flexion, reducing torso motion). That said, Simashev's skating is still really good as a prospect, and the fact that he can move like that at 6'4 remains a huge boon for the team that drafts him. If he made those adjustments I mentioned, Simashev's skating would go from "good" to "great" by NHL standards.
In the end, Simashev's mind for the game, the fact that his head is always on a swivel, that he can not only defend really well 1-on-1 but also break the cycle effectively, make a good first pass out the zone and/or also transition the puck away from the defensive zone himself if need be is what makes him such a complete defensive player, one that should be heavily coveted come the draft in spite of current geopolitics.
I don't know if I'd have Simashev as the single best "pure defensive player" of this year's draft, but he wouldn't be far-off. And I'd consider him to indeed be better defensively than Willander (better with the puck on his stick against checkers/transition), and Reinbacher (better against cycle, more stable), with a potentially more imposing physical presence to boot.
As far as defensemen rankings overall this year, my personal list would go: Reinbacher, Simashev, Gulyayev, Willander, Sandin-Pelikka, in that order. All of those defensemen have at least top-4 upside, show great promise as prospects, and I think any team that drafts them will and should be pretty happy.
Now, as far as viewing Simashev's games, MHL games are completely free to stream on Youtube, for those who want to watch him there (I think you know, but some might benefit from that info drop).
As an aside, here is a 40+ minute video for three full games by Simashev, in French, if you wanted some more insight on his game/to see him on the ice more.
So yeah, that's it from me. Cheers and have a good night.