First off, I completely love this game. The turn based combat is one of the best I've played (and I've played just about all of them), as good as (and some parts better) than Baldur's Gate 1 & 2.

But, the way the usable combat items (such as scrolls and potions) work is terrible. I hardly ever use them.

You see, with items currently in game they have the same Action Point requirement as spells you cast (and potion use 3 points).

The the main point of combat items is they should have a advantage over normal spells and a disadvantage.

Advantage
The advantage should be that you can use them when you're low on mana (or in this game case Action Points). So if you really need to (IE the combat is going pear shaped) you can still do some impressive magic/effect but with the disadvantage of;

Disadvantage
When you use the item it disappears (or uses a charge in something like a wand).
Items should be fairly rare, so it hurts when you need to use them.

But as it stands now, their is no advantage (apart from allowing characters who don't have that spell to cast it).

Without this trade off, usable combat items (in my opinion, which is also based on just about every RPG I've ever played) are just not worth it.
Yes, I've given various scrolls to character which don't have those spells but they never use them, they have plenty of their own abilities.

Solution
Simple, reduce the Action Point cost for all scrolls and potions. In my opinion change them to AP 1 but make them more rare to find and make. But of course Larian would have to balance this.
And add some charge based items (wands etc..rare of course).