Ok so the destruction staff line needs some work, most of this isnt new but I thought putting it into a consolidated list might be helpful.

For the staffs themselves, really there is only 1 1/2 usable staffs in game.

Fire Staffs- Fine dont touch them

Lighting Staffs- Since the off balance nerf lighting staffs have fallen in usefulness, even sorcs are picking dual fire staffs over one fire one lighting because its better for damage. The main reason for keeping a lighting staff as of right now is just based on how the heavy attack functions which is actually nice.

Id like to see the buff to aoe damage boosted with lighting staffs, to really cement their use on your aoe bar. It would also be cool if the splash damage from lighting staffs could provide disabling effects to more than the first target. For example, if you have Ia active it could apply Ia's effect to all the targets damaged by that heavy attack. Poisons and enchants could also apply like this giving poisons a chance to effect multiple targets or the enchant doing its damage and its effects to multiple targets. Again for example a fire enchant might damage multiple targets and give a chance to apply burning to them or an absorb magic enchant might damage multiple targets and give magic back from each target effected.

Frost staffs- Alot of players arnt happy with ice staffs, especially magdens that desire a type of ice mage build. The tanking effects that go with ice staffs are admittedly useful in pvp but even then they are arnt as usefully as aoe stuns like encase or time stop. They can be nice for keeping an enemy in damage longer after a stun ends. For pve, even for tanks it falls short as the slowed mobility really doesnt come in handy in trials and dungeons. For dps it lacking any type of dps passive function makes both of the other staffs favorable to it.

Making this staff have actual dps passives would help its use alot. For magic tanks maybe add a taunt effect to the crushing or weakening enchant? or make an outright taunt enchant. In addition to the taunt maybe it could alter the ice staffs effects to the current tank related buffs. So ice staff + taunt enchant = current ice staff effects, Ice staff on its own would have dps passives.

Ancient Knowledge The problem with this passive is it requiring a skill for the passive to be active rather than just the staff. Correct me if im wrong but I believe this is also the only weapon line to require this to gain the weapons effect. It means you have to have at minimum 1 destruction staff skill on each bar. For most players this is elemental wall and the destro ulti, both being aoe's you would want them on your lighting bar but if you do that you lose out on your fire bar having any passive bonus.

This passive just needs to no have the requirement for a skill and it would be fine.

Penetrating magic The problem with this passive is that it only effects destruction staff abilities, so it is entirely useless unless you want all of your non destruction staff abilities to be under penetrating. Obviously you dont since destruction staff abilities dont make up the bulk of a rotation so this passive just makes your destruction staff abilities always over penetrate.

To make this better just make so there is an increase to spell pen with a destro staff equipped. Also more of a personal thing but I would prefer a flat out number increase to spell pen rather than a percent even if they were effectively the same amount. Just makes it easier to know how much pen you actually have. Especially for consoles that dont have ways to tell you that information.