I feel like there are some qualities about the Uchiha clan that need to be discussed, most notably because of the polarizing reactions from people on this board: either people think the Uchiha's are ALL THAT and a bag of potato chips for no reason save "SHARINGAN IS COOL", and people who hate their undeserved popularity both within and outside of the naruto universe - especially when you consider that there seem to be like 3 actually good uchiha ninjas. As a time saver, I will bold parts to make it accessible to tl;dr readers. I think I can help shed some light on some of these issues, so please read and I hope I can explain, and perhaps even get a discussion going.
For those of you who see the Uchiha currently as pretty average ninjas and not that great, you are, for the most part, entirely correct. I say this because not a single Uchiha has risen to any sort of power since the leaf village first came into existence. Indeed, we've seen the entire clan of OH GREAT UCHIHAS destroyed by basically two guys (Madara and Itachi). Still they seem to have this undeserving reputation from characters within the Naruto universe, claims ranging from, "the sharingan should never be fought alone," to, "the uchiha are the most powerful clan and unstoppable." Indeed, they seem to live up to none of these expectations, and to be killed off so easily proves it. So why then do they have this reputation?
The Uchiha, back when Madara and his brother controlled and led them, were far more powerful than when we are first introduced to them in the manga. You know how strong Itachi is? Yea, imagine an ENTIRE CLAN of Itachis. That's who the Uchiha were. I think that example strives home how strong they were. Itachi hints that many of the clansmen would sacrifice their friends and family for the power of the Mangekyo sharingan, the sheer amount of deaths seems to be staggering. Yet when we are first introduced to the Uchiha in Konoha, just before they are killed off, no one seems to even think about obtaining the power of the Mangekyo. In fact they are willing to punish Itachi for killing his best friend, something that in the past was commonplace to gain power. It seems that after a few generations living in Konoha, the Uchiha have become complacent and lost their thirst for power - as Itachi would put it, lacking hatred.
Because the Uchiha have fallen so far and lost their will to gain power, it is not unthinkable that for this reason alone Madara killed them off. To see his clan become such a shadow of its former self, to be such a disgrace, that they had to die in Madara's mind. Just like the people on this forum who are angry with the Uchiha for being so overhyped, so was Madara - and so he punished them ruthlessly. We need only look at the example of Sauske. In Konoha, he grew to be loyal to his friends and was relatively at peace with his surroundings. Had it not been for the hatred of Itachi, he probably would have stayed there and been content. However, because of his thirst for vengence, look at the power he has obtained to combat Itachi. His growth in power over the timeskip is STAGGERING, something an Uchiha in Konoha would never have achieved. Back when Madara controlled the Uchiha, they were in a state of continuous war so they could grow strong, there was no complacency.
To sum it up: The Uchiha were once great and lived up to their title of being amazing, but over time since Konoha was founded, they fell so far that Madara crushed them. There are so many strong ninja, and the Uchiha were not even close to on par, we wonder why we could even consider the Uchiha so great. I've put forth my thoughts, and I think they're pretty good.