Players should have the ability to role-play the archetype of their choosing. Players should not be restricted from using a certain enhancement style simply because they did not want to train it.

This is your viewpoint. I disagree with it and don't take it for a given. There are some things that a player can make for another player, but not everything. And I don't think it should be everything. If you want to use the Shield skill, you train it. If you want to use Sigils, you train the skill. Some of the enhancements to gear can be done by another person, but not all.

You'll find that transmutation is also something people will need to train. Someone else can make the gear, but you need to do the transmutation (re-rolls) yourself as that attunes the item to you. Transmutation takes some work, but turns random mods into the exact set you want.