Count Dooku -- There is a missed opportunity, make him the trainer/master of Maul, with Sidious as his master. I know that wouldn't be "canon" but it would fit better, imo. Why ascribe the clone army to some unknown Jedi, just admiit it was Dooku.
The Labyrinth of Evil novel provides some back story on the origin of the Clone Army. Apparently, Sifo-Di-yass became disenchanted with the Jedi when Qui Quon Jinn died and started looking for ulterior ways to save the Republic from itself. Dooku also started looking and became an easy target for Darth Sidious to corrupt. Before his untimely demise, Qui Quonn was a leader of a Jedi faction that was more far-sighted than the current Jedi Council including discovering how to merge with the force after death. Yoda did not realize that Qui Quonn was correct is asserting that the Jedi were stagnating in fossilized practices, that would eventually allow the Sith to overtake them, until the Emporer proved in his duel with Yoda that the Sith had evolved to the point that they were more powerful than the Jedi masters, like...Yoda. After losing his duel with the Emporer, Yoda became Qui Quonn Jinn ghost's apprentice in order to find new unconventional ways to eventually defeat the Sith.
Anyway, when Dooku found out about Sifo-Di-Yass probing the Kaminoans about making a Clone Army, he told Palpatine and the Sith Lord gave as his first task to kill Sifo, but only after the Clone Army idea was well underway. Then Dooku went and found the clone template by hiring the bounty hunter Jango Fett. Palpatine also had ex-Chancellor Valorum bumped off in a mysterious shuttle accident in Labyrinth of Evil. The Old Republic Intelligence services also manage to link the warehouse used at the end of Attack of the Clones to someone in the high levels of the Republic gov't. But, when they arrived at Palpatine's door a couple of Genosian guards waxed the investigators with Palpatine smugly walking over their dead bodies on his way to the "kidnapping" rendezvous with Grevious.
Lucas wanted this to be "epic" but he made it too epic, covering too much time and space. All we really cared about was seeing Anakin, the young Jedi apprentice and his turn to the dark side. We didn't need an immaculate conception, pod racing and the whole discussion of mitochlorians(sp?). Everybody wanted to be a jedi when I was growing up, I guarantee that had we know about mitochlorians in the 4th episode we wouldn't have given a damn. Now we have Anakin turning to the dark side and if his resume just includes:killing younglings, getting mutilated by Obi Wan on the volcano planet, being unsuccessful in tracking down the plans to the first Death Star when stolen by the rebellion, not being able to stop the rebellion in destroying the first death star, letting the rebellion escape Hoth, the snow planet(you can only blame so many things on underlings), losing the Falcon in asteroid field and then falling for the oldest one in the book, escaping with the garbage, not delivering Skywalker the first time, and then on the second confrontation with Skywalker giving in to the light side and helping to destroy the Emperor. What kind of evil resume is that? What reason do I have to fear Vader, he's not been succeessful at anything hes attempted, on either side. Lucas has made the main character of two trilogies a complete and utter loser and that is laughable. Now my recollection of Vader is him breaking bonds like Frankenstein and screaming "NOOOOOO!!!" Give me a break.
The Sith were basically having everything go their way for close to 32 years from Episode I until right up to the moment Luke destroys the Death Star. Only when the ghost of Obi-wan Kenobi, using skills taught by his own master Qui Quonn, instructed Luke on how to destroy the Death Star and with some vital unlooked-for help from his friend Han Solo, did the Sith start losing. Basically, Lucas was big on how friendship and love can always overcome evil, because evil, in the end, is all about being selfish. Not until people started giving up their old ways (ie. the Jedi Council opposing Qui Quonn Jinn's teachings), and the selfish corruption of the Old Republic gave way to people freely giving their lives for others, did the Sith start losing. Finally, when Anakin finally grew up and gave up his life to save his own son did Darth Sidious die. But before the first Dearth Star blew up, the Sith had a pretty good run: engineered the Clone Wars as a vehicle to kill Jedi and dilute their numbers in preparation for the Jedi Purge, Jedi Temple destroyed, Galactic Empire handed to them for 3 plus decades, Alderaan destroyed, etc. Actually, about the only thing missing from Lucas' careful re-construction of past RL intriques in the ancient Roman Empire is Jar Jar Binks mimicing Emporer Claudius, who as playing the fool survived all the back-stabbings of the Augustus dynasty, to eventually become Emporer of the Roman Empire, ruler of 1/4 of the ancient world's population, and conquerer of Britain in the 50s AD. :O
BTW, does anyone find it interesting that the coming out of "Deep Throat", who was the vital source in the FBI to fuel the Watergate Scandal investigation, the informant that displayed the corruption of the Nixon Administration and its misuse of the CIA, FBI and US Dept. of Justice to the world, occurs when ROTS comes out? Lucas always said Star Wars was a reflection of the times during the Vietnam/Watergate scandal era in addition to his probing on why the Roman Republic and the French Republic of 1790s eventually became empires. Corruption kills democracy indeed...