Making the skill checks higher would only make it frustrating for parties that don't have Guidance and Friends etc., thus making those spells effectively mandatory unless you want to fail at everything.
The focus should be much more on character skills and abilities than buffing spells to begin with. 5e does a really poor job of making skilled characters actually feel that way. And Larian are making skills feel even less significant by making these buffing spells so convenient to use without any consequences.
I think at the minimum, we shouldn't be able to use a character's buffing spell on checks against that character (ie using guidance against shadowheart)
