Originally Posted by
sanahtlig
Putting aside the fact that two weapon skills are usually better than one, and you won't have a wide selection of SSR weapons to choose from, equippable Burst buffs are not especially good, and I explain why in my Accessory buff guide.
Remember that Burst damage starts with a 5x rather than a 1x multipler (for SSR kamihime). Therefore any Burst buff's effect should be divided by 5 to approximate the effect on damage. Shingen's ability is a +200% buff, which is why it's so powerful. To get the same effect with weapon skills, you'd need 7 SLVL20 (small effect) weapons, which would yield +42% Burst damage. Meanwhile, 7 equivalent Assault skill weapons would give you +70% character attack, or +31.5% damage. Would you rather have +31.5% damage all the time, or +42% damage on Bursts only?
In short, Shingen is good because her Burst buff (+42% Burst damage) is uncommonly strong vs. the alternatives available for character ATK (e.g., +9% damage from Arthur). Throughout the rest of the game, you don't see that same lopsided ratio.