heroes of slowing and earth magic

Currently, changing the spell level or its school affiliation is considered an unacceptable action, so it's best not to even discuss it. However, the following are fundamentally permissible: 1) Modifying the spell's mechanics. This is also not ideal, but it is acceptable in difficult cases. 2) Adding new spells. There are fewer restrictions here. By the way, this is the answer to the question "What needs to be done for this?" - propose a good system of changes to the magic system. So that both aesthetically (to the developers' taste) and in terms of gameplay (to the players' taste), everything is neat and tidy.