We'd naturally be doing a test run. If I see things don't work, I'll bring back the previous system. It's not like we are making a step that can't be traced back in case of trouble.

As for Magical Freedom, I'll be giving individual guidelines as to what can and can't be done. Hell, in several cases, yellow text can be used as a base. You'd be free from the yellowtext in the sense that you will be able to use it in a more creative manner, not outright change the general purpose of the spell. For example, Mikoto's Isanagi is a spell which enforces peace and harmony focused on defense with a touch of support. Mikoto could now use it to calm the waters of a river by touching it (just an example) which, going by yellowtext she couldn't do before. If however, she tried something that went against the general purpose of the spell, she'd need to buy the proper branch spell.

Kamui can be used to replace items for others, enhance them and provide some weak conceptual support to mikoto and other people. Now Sei once managed to teleport using this power, which is in fact possible, but goes against its general purpose (which if you are lost can be seen in the yellow text) so I told her to make her own branch spell for it. This won't change. If Sei wanted Mikoto to use Kamui for offense purposes, she'd need to pay a visit to the GP shop as well.