I love it. It could be used as a purely defensive weapon, keeping enemies at bay. I can see it being favorited among thieves, fending players off as they make their escape. The specials are already obvious:
"Agility and skill are more important to master the weapon rather than strength or aggression. Twirling and controlling the urumi is a difficult and dangerous art, and is therefore taught only to the best. The urumi is most useful against multiple opponents."
- This special would do a series of rapid area attacks, causing bleeding on occasion. The down side to this attack is you must be standing still during the attack, making it a defensive move. Obviously, it wouldn't be very useful against mages.
"When not in use, the urumi is worn around the waist like a belt."
- This would be so amazing that it is a must for this weapon to be holstered around the waist. As the second special, Holster would give a powerful defensive bonus, but leave you unarmed (you couldn't use a different weapon while this special is in use, that way no one could use this as a permanent alternative to a crimson cincture/tangle). The holstering bonus would have to be worth not wearing another waist slot, and having to remain unarmed for the bonus to take effect.
"Incorrect use can result in the flexible sword wounding its wielder, and great concentration is required during use, even by experts."
- This weapon would have a new skill of its own. A low skill would cause you to occasionally harm yourself when attempting the area attack special. Raising the skill increases the Holster defense bonus, and the speed of the area slash. 120 would cause the speed of the area slash to be the fastest attack in the game by far, allowing it to be worth the 120 skill points. In fact, maybe it would be best for this weapon to be a standard 100% physical attack weapon, only upgraded via the weapon skill. The super fast standing area attack combined with the defensive bonuses (maybe allow them to be selected through a menu as you raise your skill, being as though this is the only way to upgrade it) would make this weapon/skill the most unique in the game.
Regardless, this weapon has a ton of unique potential.
P.S. The preceding message is just me thinking out loud. Do not read too much into my ideas.