Is it really a that big thing to add?
Darn.. Guess I'll just have to bore myself to death when always attacking in the same way..
Yeah it kinda svcks. If you're not using too many mods, Combat Enhanced might be a mod worth looking into. It doesn't change the animation, but you use the default system with thrust, slash, and chop attacks to create combos like a fighting game if you've got enough skill in a particular weapon. The combination attacks are well done and sort of help get rid of the monotony. They also encourage you to use a variety of weapons just to get the benefits of all the cool effects. You'll also have "rage" and "trance" modes that can slow down time to perfect your combos.
I say "not using too many mods" because CE can increase crashes which is pretty frustrating. You'll still be able to play through the game, but CTDs can really discourage someone from continuing to play.
Another mod worth checking out is "Realistic Combat". It doesn't change animations either, but it does allow a 100% hit rate and running/jumping strength bonuses. The hit rate change makes combat a little more strategic, with more emphasis on quickly getting into hit range and getting back out before you can be counter attacked.
You can combine the mods as far as I know to interesting effect, although a couple of the weapons become extremely unbalanced as the first combination attack you get can be quite powerful. In particular, Long Blade will have a knock-down attack and Realistic Combat makes attacks to a downed opponent even more devastating. But with some other mods to balance this out, the combat experience can become really fun even if there are only a handful of animations. You'll find yourself thinking strategically and switching weapons a lot instead of just picking your best weapon and getting in your opponent's face while hitting your mouse repeatedly.