That's a great idea! Keeping the spirit of the movie's overall intended form, but answering the lingering question of Sifo-dyas' role, while expanding Grievous to a richer character with an overarching purpose. It reminds me of something related (though more extreme) I posted years ago on Trooperman's edit page, which, quality or no, might be worth digging up for refreshed discussion fodder:

In my opinion Qui-gon ought to actually have been involved in the plot. Sifo Dyas' eventual explanation in extraneous material had him a Jedi who had premonitions of a conflict involving the death of many Jedi...I would go even further, having Qui-gon ordering clones knowing it would lead to the dissolving of the Jedi order and thus on the path to bringing balance to the Force. (even his last words betrayed him to be rather obsessed with bringing that balance). It could, MAYBE, be shown that in TPM Darth Maul was sent, in addition to what is already shown in that movie, to silence Qui-gon from potentially prematurely revealing the plans... but that's maybe a tall order.

Qui-gon should not be knowingly working in cooperation with the Sith. Though, following this idea, it could be revealed to him during the energy shield breather in the duel section of TPM. Conveniently, Obi-wan is out of earshot while Maul could conceivably let spill to Qui-gon the Sith's involvement, and his scheduled termination. This gives added focus and reason for Qui-gon to redouble his efforts to defeat him, and to plead with Obi-wan to go ahead with Anakin's training, which would lead, eventually, to the destruction of the Sith.

Interestingly, again in the EU, Grievous is made cybernetic with the help of a blood transfusion courtesy of Sifo Dyas! This in itself is...kinda lame, but maybe something in the same spirit could be transferred to Maul to keep his character relevant to the overall plot. At the same time, though, both characters are kinda unimportant to add additional and unnecessary convolution.