Kyrou is not THE problem with this team. There are a few different problems with this team. Too many of their player assets, and too much of their CAP room is tied up in contracts of older players that are too slow, and going to get slower, and on the downside of their careers, and their defensive roster is inadequate, and most of its better players are nearing the end of their primes, and need sheltering because they are much weaker on the defensive side than the offensive. Goaltending in inconsistent. The Blues young talent is still mostly inexperienced on the NHL level, and there are not enough NHL ready.
Kyrou might become a weakness if he continues to have very slow progress in improving his defensive game, and make very slow or little progress in his play without the puck, team game, and learning to finish better by sharpening up his goal scoring by working on puck control and finishing moves.