FormerlyHemlock
Hero
And I do agree that insight might not be the best defense, it seems to be their go to “defense stat” for persuasion, deception, intimidation, ect. A morale stat could be good for stuff like that, but I doubt the designers will add a new stat for this section, we’d have to homebrew it in… or wait.. isn’t there a variant for morale in the DMG? I’m AFB, but I think it was with the Honor variant.
Using the same defense stat for persuasion, deception, and intimidation is a design mistake on their part because they work differently.
Insight is a reasonable "defense stat" for deception. If you see the truth, you don't get deceived, period.
For persuasion, higher insight should actually make you easier to persuade, not harder, in any case where persuasion (vs. deception) is applicable: that is, whenever the thing you're being asked to do is actually in your own best interest, such as changing your mind when presented with a valid argument. If you see the truth, you accept the truth. With low insight you might stubbornly refuse to change your mind; or you might turn down a deal that benefits you (5% profit) just to spite the other guy and hold out for a 20% profit that won't come.
For intimidation, higher insight should make you more accurate. If you see the truth, you get scared by beholders and dragons and archmages, but not by random peasants pretending to be archmages. But higher morale should determine whether your quite-rational fear manifests itself in physical and mental symptoms like hesitation which impose the Frightened condition, and that has nothing at all to do with your ability to perceive truth.
I think the DMG variant for Morale just says to use Wisdom saves. I remember I thought that was lazy design.