Oh get over yourself.
Thu'um represents a challenge for me in terms of how to RP it and not take advantage of it. It's like a spell but without any need for magicka or stamina, it's a powerful attack that can come at any time and one that appears to have an infinite number of uses. It effectively gives combat characters, who have no knowledge of magical spells and stuff like that the ability to have a non-melee/bow attack.
So, they're really just Spellswords and Battlemages with a PhD in Manliness.
Already it sounds overpowered, it has no obvious disadvantage - You can "shout" it whenever you want, whether it's exhausted or near death. There are no rules as to how you can use it.
Well, it's nowhere near as versatile as magic, and you can use normal magic whenever you want (As long as you have magicka)... But from what we've seen from a Gameplay stance on Thu'um, it looks like that instead of having to rely on an arbitrary "magicka pool", you can't shout incessantly: it takes quite a substantial amount of time between shouts, and the more powerful the shout, the longer it takes before you can shout again. Kind of like having an independent "magicka pool" strictly for Thu'um use that you have to wait to recharge
completely before you can use it again.
In combat, thirty seconds is a significant amount of time.
Outside of combat, Thu'um makes for little more than a glorified party trick.
From what I have figured out in Skyrim, the Thu'um is not something everyone is aware of. It appears to be quite a secretive ordeal - With you having to prove yourself to the greybeards before you're allowed to continue training. I have also yet to come across any books detailing the Thu'um so training outside of the greybeards would appear to be something rarely experienced. It was also noted that the greybeards mentioned how long it took to master a simple shout, even the very first word was said to be extremely difficult and to take many years of hard study.
My question is how hard should it be to use Thu'um? Like magic, we expect characters who are well versed in schools of magic to at least have a history of study or practice and to show that through study. The same thing for melee and ranged combat. To expect a gladiator to be a master of conjuration is just impractical as they wouldn't have time to study that school of magic.
From what I can tell, Thu'um does need to initially be studied like magic. Unlike magic, though, it requires a minimum amount of Manliness to use. While you can learn the very basics of Thu'um from bookwork and secluded practice, however, you need to
really work on and master the use of the language in battle, when you
really mean what you say.
How do we control the Thu'um? Unrelenting Force, the Fus Roh Dah Thu'um takes around 30-40 seconds to recharge. Making it quite easy to rinse and repeat. When should we as GM's limit the control of it?
My problem with the Thu'um is there is no viable way of me telling someone they are ubering. As a GM, I am in charge of making sure everyone is having fun and the enemies are challenging and engaging. If someone is just walking around casting fire breath at everything they see. I need to tell them to stop ubering and so and so.
The way you handle someone who's just walking around casting Firebreath at everything they see is handled the exact same way you handle someone who walks around stabbing everything they see. Try knowing the abilities of your player's characters and design encounters based around that, instead of going "OH NOES! NERFBAT TIEM!" and trying to force everyone to conform to an arbitrary, narrow profile of character archetypes that you believe are "balanced".
The time to decide whether Thu'um's acceptable is at character submission. But then, it's not from a balance standpoint: it's based on verisimilitude and the scope of the RP. Only the manliest of the manliest men (Or equally manly women) in Tamriel can use Thu'um: it makes sense to restrict it if a particular character having it would give the feeling of "Everyone and their grandma is able to use the voice."
Only a few men per generation can use Thu'um. If your RP doesn't allow for notable heroes, warlords, or other such Manly Men, then you shouldn't have to worry about Thu'um.