I'd say that it's hardly fair to slam guys at such a young age... especially a guy that really had limited coverage leading up to the draft and in the year following. Kastsitsyn just turned 19 in February and put up killer numbers in for CSKA-2. No, it's not the RSL, but look at the RSL as a whole... there isn't a lot of scoring, defense is king, and he saw limited action for 11 games of a season. Not exactly a prime situation for AK to score 20goals and blow you away.
Here are some possible reasons...
1 health
2 racial/nationalistic tension with the coach/management
3 punishment for the whole zherdev situation (ie they expect to lose him sooner than other guys so why bother to play him minutes you can give someone else)
4 played bad defense
5 personality conflict
6 didn't fit the needs of the team (ie if he's not getting lots of O-time, and he's ineffective as a closer, then you're better off with him on the bench or elsewhere)
7 spends too much time at international events... coaching staff doesn't approve?
8 russian hockey is CRAZY POLITICAL
Personally, i'm not worried. All reports i've heard from people who know what they're talking about (eg Savard, Timmons were over earlier this year, and our good friends from RLR answered an email from a curious poster) say that the kid has outstanding talent and that there is nothing to worry about with his development.
Personally i'd keep both... keep AK because we've had limited viewing, and keep IG because he's recovering from an injury. It's a simple premise, you only trade from a position of power (ie a prospect who is bound to get you the biggest return). Either one of these guys could breakout next year and take the NHL by storm...
Also, RK didn't have that great of a season... why trade 1 or 2 potential offensive stars for a guy who may not ever realize the potential that everyone claims is there. Heck, look at Malakhov... awesome skills set, huge potential, but it never came together for him here in the NHL.