It is unlikely that they add this in the game so late if it isn't already in, but it could perhaps make a nice DLC, or be included in a further, bigger extension...
Here are just some examples to make my point more clear...
For fire spells, a mage could for example put both hands on his ennemy's temples, the ennemy screams briefly while he attempts to pull the hands off his head, just before his skull burns from the inside, flames rushing out his mouth and eyes-sockets. The burn-from-the-inside-thing could be adapted to a fire staff, the only difference being that the hands on temples are ennemy's, due to the pain he feels...
For a poison spell, the ennemy could begin to bleed from the eyes, mouth, nose and ears, he staggers, drops his weapon, fall on his knees and finally dies. Or he begins to cough violently, or to convulse.
For an illusion spell, the ennemy coul be forced to commit suicide by falling on his own sword.
For an absorb health spell, smoky brambles linking the PC to the ennemy could force their way into the latter's very veins and svck his blood while he becomes livid.
A flame-thrower spell could become a fire snake that rush on the ennemy.
With a shock-spell-enchanted gauntlet, the PC could grab his opponent at the throat in a strangulation-like movement and shock him till death comes
Do you think it would be a good idea to put things of such kinds into the game?
These are only examples, I don't even know whether the game engine allows for these, but since an idea never shared is forever lost, I felt the need to post this.
If you have other examples - and I'm sure there could be many - or reasons to say that this idea is very bad, please post them...
Verbose.