I'm going to start off by saying yes I am a bit biased against the Uchiha. I feel that the clan had a huge stranglehold on the plot that drug it down and that the Mankegyo Sharingan was way too overpowered. Couple that with the fact that the Mangekyo was supposed to be rare, but half a dozen people had it and the vast majority of those people are turds and you get a cluster of stupid.
That being said, even with my bias against them I have to wonder why on earth did the Uchiha clan think that they could take over Konoha? Why did Kishimoto think people would buy that? I'm not saying the clan didn't have strong members, but let's look at this logically.
First off, the clan was just that. A clan. One clan. Many members of the clan do not fight. Some of the members likely don't have fully awakened sharingan. Some of those who do have it may be too old to fight for long. The clan had been in decline for a while so it didn't have a large pool of fighters. There are seven or more clans in the village. One of which is the Hyuuga whose Byakugan can match the base Sharingan in terms of power. They had been rivals for awhile, but since the Hyuuga weren't under survelaince and marginalized it's safe to assume they had more members, better funds, and etc. I do not recall the Uchiha having any allies to help them in this rebellion and please correct me if I'm wrong, but that alone speaks of their arrogance. To think they could take over the village with a few squads. They could do damage yes, but no one would let them take over.
Secondly, their heaviest hitters were not there. Shisui died, and they knew Itachi wasn't likely to side with them. Even if Itachi had sided with him they still wouldn't have one for Itachi would have run out of chakra trying to deal with heavy hitters like Guy, Kakashi, Kurenai, Asume, Danzo, Yamamoto, Jiraya, Anko, the other clan leaders, Anbu, Root, the Third Hokage, and etc. He got winded after one use of Mangekyo when he fought Kakashi several years after the rebellion.
Thirdly, the other clans are not slouches at all. Hyuuga are monsters in melee who will see you coming and tell everyone hey look there are the stupid Uchiha. The Nara in an urban setting with shadows everywhere? Please. The Inuzuka with a massive pack of ninja hounds? Have you ever been attack by one dog? I have it's hard dealing with one, let alone a pack of them and their rabid masters. The Akimichi can turn into Kajiuu and slug it out with tailed beasts. Remember Chouji fighting out with the geddo statue? A fire ball isn't going to do much to him. The Aburame. Just no. One can control a swarm of thousands the entire clan would blot out the sky with their insects. They're sneaky and can breed their insects to do various things. Then there are the Yamanaka who terrify me the most. They can take over your body, they can make your ally attack you so you have to deal with that before getting to them, then they can trap you in a freaking doll. A DOLL! In a one on one clan fight I can see the Uchiha beating these clans, but that's the problem. It wouldn't be one on one especially with the Akimichi, Nara, and Yamanaka. That trio would crush the Uchiha easily.
Fourth and fifth reasons. Might Guy and Jiraya. End of story no explanation needed there.
Sixth, the village knew they were going to do it. They were prepared for it. Even without the clans the village has a pretty large shinobi force. Root had likely been trained to fight Uchiha so this was a rofl stomp in the making.
This plan was doomed from the start. All I see is a waste of life, resources, and stupid pride in this action. Maybe I'm reading too much into or hindsight is 20/20, but really don't think that in character this was well thought out and Kishimoto didn't think it out either.