I'm not trying to argue your wrong but why? From an out side perspective it seems like it's very hard for players to successfully leave the Russian system and if they do it is not always a smooth transition. Like I said I don't know anything about the mhl. Khl yes. But if you have more information or insight on Russian players benefiting from Russian leagues please explain. And again this is for a better understanding not calling you out on your points
The most striking points tome are:
It is indeed a different brand of hockey in Russia. Players leaving too early are basically in the situation where they haven't finished their learning of the russian style and then are forced to have a crash course in NA hockey while dealing with a culture shock of transition to a life in a diffrent country, learning a language and so on. In many cases they basically fail to take from both systems and even start losing the traits they had. Again, having a talent level of a guy like Ovechkin they not only manage to adjust, but also go a completely different path, i.e. getting a NHL roster spot early instead of going the whole path of CHL, AHL over the course of 3-5 years. For a 17y.o. who isn't a consensus top 10 pick the early change bears way too many dangers. The culture adjustment may fail, the style of hockey adjustment may fail(and let's face it, for quite objective reasons the coaches in the CHL won't spend too much time on a guy who struggles to adjust, that's not peewee hockey anymore), the things the guy learned in Russia may fade instead of being perfected. It also has to do with age. That's why I see that 21-23 as a good age to leave. They are much more mature at this age and have a better understanding of what they're going to face and the level of personal responsibility. And I think it is obvious it is a completely different path than that of a canadian kid spending his whole development time in the same system and smoothly growing his way through all the levels. So it has nothing to do with the quality of the development system itself, as both systems are different but very close in quality overall.
And that is the other point. There are some significant differences in the russian league system. Most MHL teams are directly affiliated to a KHL franchise(and basically there is a 3 team conglomerate there MHL, VHL and KHL). The best part of it for young players is there are no such age limits as in NA. The KHL basicallly allows 17y.o. to play(if they are that good obviously and with some restrictions). If the young player is good enough he'd get to play with the grey beards earlier. And there is much more movement between the leagues. Obviously it's a rare case a 17y.o. is good enough to spend a season in the KHL, but having some stints to see what the game for the big boys looks like is a valuable experience and the player can spend the rest of the season in the MHL(or VHL if the team thinks he's better off there with grown ups, but not quite ready for the KHL yet. that's another sub-point.in the russian system all prospects are in the same franchise system and their development can be watched more closely by the coaching staff, while in NA scouts would monitor prospects playing on different teams in different leagues.). There is no 9 game rule. Players can be called up to the KHL and sent down throughout the whole season. That adds flexibility to the development system.
The often heard critisizm(also in Russia) about young guys riding the pine too much in the KHL should be taken with a grain of salt. The KHL is not a development league after all. Nobody will give a roster spot to a young guy if he's not contributing to team success and oviously it's harder to get a roster spot on a contending team. On the other hand if a young palyer is that good nobody in his right mind will glue him to the MHL, while obviously every KHL coach has a mind of his own too. So it's not a league thing. Every player's development situation is different. Oviously while Sibir wasn't a contender a 18y.o. Tarasenko was a top line player there, but he'd maybe get much less minutes on a different team. While bottom feeders like Kuznya are perfect places to shine for young guys every season.
The other point of critisizm being the level of competition in the MHL is also way off the mark in my opinion. While the MHL is still young and going though growing pains it develops just fine. One of the good moves on the road being relegating weaker teams to MHL-B. There may be less parity in the MHL than in the CHL which basically derives from strong KHL franchises having their own well built development system starting from kids hockey to the MHL and VHL teams. Those heavywheights obviously dominate the MHL, but there aren't too few. It's not like there are 2 good teams and the rest are punching bags. Also since this season the russian U18 NT competes in the MHL. Too early to evaluate so far, but for a small sample size it works pretty well as they look on par with the better teams(being of course younger) and while the team is a good competition for others it's also a good place for development for U18 prospects.
There is also often an attempt to compare the CHL to the MHL straight up which is wrong. Firstly because while there is more disparity in the MHL there is still enough good competition in the MHL and MHL's better teams are well on par with CHL's better teams and then for development I think you'd have to look at the system as a whole which would include the aforementioned advantages of the MHL/VHL/KHL system. That paired with the fact that russian players should not drop their unique russian part of the development unfinished at 17 makes me think the better way for russian prospects is to stay in Russia a couple of years longer. After all it didn't destroy Tarasenko's of Kuznetsov's development. While I do admit every case is different. I for example have no trouble at all with Provorov's decision to go to NA really early. There is obviously a glaring hole in the russian system at the spot where defencemen development should be, so it's only logical for a guy like Provorov to try another path and it seems like it wasn't a bad decision.
There are also 2 major factors that influnece the decisions of the players to go to NA. There is that partly russian factor thing about coaches and management in NA who for whatever reason want to have the player in NA as early as possible which is sometimes illogical. I basically thik that a lot of franchises have little idea about russian hockey and just fear they can't evaluate if it's good or bad for a prospect to stay in russian hockey. And then there is the draft factor. At such young age players want to be drafted as high as possible no matter what and for the sake of exposure before the draft go to NA early. I think though while the draft position might affect the future career in a way, it's not that important. But the young guys have minds of their own(or their parents and agents for that matter).
I think in a perfect world every player should carefully evaluate which path is the best for his development(not exposure or draft ranking) longterm. It's not a perfect world though.