Staves can take advantage of the "Opportunist" talent. Which can be quite big in some cases
With a stave, you can also attack from range (one time per turn, but if you are a caster, that's usually more than enough)
minor: If you put points in 2h instead of dual wield, you get more crit damage as well instead of dodge
Wands are hands down a better option in terms of damage, if staves are not good at that they should give other benefits, what you just said is terrible and not worth it.
