there's just not that many prospects that safely project to be top 6 centers. the few that do are either already in the nhl (celebrini, bedard, smith, carlsson, fantilli, cooley) and will cost a mint to acquire or are basically untouchable (dvorsky, catton, ritchie, lindstrom). you can maybe pry loose a guy like danielson or kasper from detroit or beaudoin from utah or maybe danny nelson from the islanders but those guys are not safe bets to be top 6 guys and might be years away in the case of someone like beaudoin