I think NPCs should become hostile if you use some magic on them ...
If you are casting some spells on your friends, its between you two to figure consequences out. :-/
My problem is casting it on yourself in front of the NPC ^^ You are basically making obvious your intent to magically influence the outcome of the conversation. I would be really pissed off if someone do that to me xD
Before the patch from what I remember, people complained that using guidance was inconvenient.
It is more of a QoL change, thanks to which you do not have to know where the check will be difficult, then cast it and make a conversation before the end of the spell.
