Trap the soul is a very nice spell but is limited to 30 or lower HD creatures. Of course nothing in D&D is supposed to have more than 30 HD yet we do in DDO because of inflation and developers not having any better ideas on how to challenge the players.
The 30 HD means this spell is worthless in EE.
Let's make it not worthless in EE . . . make a material compontent that can handle up to a CR80 soul.
Have the TTS spell use an Astral Shard for souls over CR30.