To put it bluntly, the abilities in DA:I suck.
They feel weak, look weak, are weak, and they cost way too much mp.
And where are my spell comboes? DA:O did that right, DA2 and DA:I got it completely wrong.
And the abilities are so meh in terms of how they used to function and feel in prior DA games. A great example is DA2's Cone of Cold, an extremely useful short range AoE that would instantly freeze all enemies in a short arc around the mage while also doing decent damage. This is the type of spell you use as soon as a melee unit sneaks up on you. There is no functional equivalent to these types of spells in DA:I. In DA2 a mage was able to constantly cast spells, provided they had enough spells to cast while only rarely having to rely on autoattacks, and so the mage had access to lots of fun utlity spells like Cone of Cold. DA:I is significantly lacking these kinds of spells because of its awful decision to focus on autoattacks over casting spells. And the spells we do use, when we are privelaged enough to be able to cast spells instead of more rote autoattacking, are just so completely meh. I mean by this that the spells have long coodlowns, short durations, low damage numbers.
The DA:I mage is no longer a mage, it is now a focused mezzer hedgewizard, trying to use the hedgewizard's weak magical abilities to impress some hapless villagers to earn enough coin to buy dinner.