Seeing the Vermillion Knight taking his Eternal Control shard, Saleen knew things could have still gotten better. Unless the Vermillion Knight was killed by his family badge, he would still have ways to restore the knight. Even if it were restored, the grade-10 Vermillion Knight would be one without a soul, making advancement impossible.
An elemental badge lacking the possibility to advance was not something Saleen would consider to be of great combat potential. Doing so in the long run would only cause the powers possessed between the six elemental badges to be unequal. When a true professional was encountered, the elemental creatures' weaknesses would be exposed. That would then cause them to be easily defeated by some special skills, such as an eerie spell like Dismantle Element.