Dear SilvioArjunza,
As far as I know, kits are made with WeiDU nowadays.
CamDawg's Kit Creation Tutorials are very good for that.
However, you won't be satisfied if you seek an editor with a user-friendly GUI. Modern mods are based on
WeiDU, so no matter how much the black windows aren't tempting, sooner or later you will have to learn how to use it. This is essential for the compatibility, to ensure that your mod will be compatible with other mods and can be uninstalled or reinstalled easily.
P.S.: WoRM's forum description says that new spells can requested here, but it is related to the graphics of the spell.
So you posted your question in the wrong forum. This thread will be moved to the General Modding Discussion forum soon, so you will be able to find it there.