I dislike staves as a combat weapon. I'd rather they stay on your back/holding place until you cast big spells that require the staves ability to 'focus' magic. I dunno slinging chain lightning, energy barrage, and immolate with your hands sounds so cool. Use the staff for the big stuff like Static Cage, Blizzard, etc.
Well the problem with this is they would have to rework the mage combat model. Even in DAO you were throwing bolts with your staff while you were waiting for mana or spell cooldowns -- negated at higher levels by the large mana pool and variety of spells, meaning you always had something to cast -- they just got extreme with the animations in DA2 and DAI, as well as having an actual DAI skill (barrage) based around shooting bolts from the staff (one of my favorites).
The solution to not using the staff as filler would be to have a few core spells -- low cost, low damage, mostly single-target, that the player fired off continuously as they waited for The Big One to come off cooldown, or for the mana to accumulate for its use. I'm not sure if I like this idea, simply because it would remind me of the World of Warcraft caster combat model where you are continually casting something and you typically have a set rotation to maintain maximum DPS, and if you fall away from this your DPS drops like a rock. I think this would make the mage class seem too tedious during general combat.
I also don't think it's very 'realistic' (yes, I know...) In the DA novels, the combat scenes where mages are involved typically see the mage hanging back, waiting for the best opportunity to throw out a fireball or whathaveyou. And of course they also must be wary of the positioning of allies (friendly fire!) relative to the enemy. It actually takes a lot of effort and concentration to fight with magic, something that hasn't really been reflected in the games, and can't be if you are to keep the three classes on an even level as far as playability.
In short, both of the non-mage classes have an auto-attack that they can use as filler, and the mage class should have something similar. Unfortunately this involves using the staff. BUT I do think that they should try to find a better balance between auto-attack filler, and also tone down the animation a bit. The DAO staff animation was terrible, but the DA2 and DAI style go to the opposite extreme. There needs to be a balance.