It would unfortunate if he was unwilling to play in the AHL.
The advantage to the time in the AHL is that it is a development league too so he can work on parts of his game and get more playing time.
Not sure it’s less competitive in terms of talent levels then the current KHL or how great the coaching he’s getting either. If he can produce and/or has a solid two way game then he should make his way to NJ sooner than later.
Largely less competitive. 8-10 really good players is a loss, but not as big as gap between leagues. In the KHL, 18-19-year-old boys have never really good in scoring and are not gaining as much as in the AHL. The AHL is not a competition league, it's a development league, just like you said. But the level of Gritsyuk's competence is already at a really good level not to engage in simple development. We can observe a similar situation with many hockey players who are already good enough for the AHL, but not enough for the NHL. And often in their case, the best way out is just to let them play, fail and train in the NHL. Do we have such a privilege ?
Gritsyuk (in my opinion) is not ready right now for a role in the top 6 in the NHL. And if you choose strictly between full season in the AHL or in the KHL, then there is nothing to discuss here - if he has to work something out, he has to work it out in a more competitive environment with tighter hockey, in which the cost of error is higher.
But his choice is lookin differently. There are a lot of details and specifics - possible call ups in the NHL, possible work with NHL coaches and working out with the players of the squad (what Holtz is going through now). How much it is better or worser is very difficult to argue, I am sure - in each case it gives an individual good or bad result.
So I don't see a problem in either outcome.