Excruciating wounds, thematic changes

[thomson1]

How about changing it into Nec/Hex and making it curse your weapon? You literally curse the weapon into doing more damage. Usually in stories weapons powered by dark magicks have some sort of drawbacks built-in. I don't think it would be necessary to delve in too deep trying to come up with negatives with the spell, but a change like this would give it some flavor and differentiate it from the other branding spells a bit.

Cursing a blunt weapon wouldn't be too bad since if you've got Nec you can grab animate skeleton and get your chunks that way.

If it's a major drawback maybe drop it down a spell level. Or just make the curse temporary. Or have Lethal infusion temporarily curse the player's weapon in a similar fashion as an introductory spell into necromantic weapon boosts, then have ExWounds give a permanent curse. Something like that, just bringing in other 'costs'/balancing factors to spells than just MP&difficulty casting (I know there's loudness as well).

[cerebovssquire]

"it's flavourful" is a really bad argument to implement something. Especially when this "flavour" comes at the cost of tedium, since butchering with Animate Skeleton all the time or uncursing your weapon constantly is boring and repetitive.
Also, both spells are already more on the weak side (I barely ever cast either of them), so nerfing them even more is a bad idea.

The "pain" brand is already different from all others because it increases in power with another skill. For others it merely depends on weapon skill or in the case of chaos, luck.

just MP&difficulty casting

The difficulty of casting isn't just success but also hunger. Spell slots restrict you. To a certain extent, your XL restricts you.
In addition, we have quite a few spells that backlash on you or are only adequate in certain situations (take Death's Door).