We already have a process to determine the riding in the City - it is a federal process that solicits input from the local government and citizens. Why reinvent the wheel when the process already exists. The City is not getting smaller any time soon, so the same philosophy can be used for years to come as the current 25 ridings (wards) would increase to maybe 30 or 35.
I think the one thing the City has too much of is local representation. There are 44 Councilors who are only concerned about there few square kilometre area, and only 1 mayor who has the interests of the City as a whole. I agree with the above that if local representation is too difficult, it should be handled with additional assistants, and not more Councillors, who would have the effect of farther weakening the power of the mayor.
To increase the power of the mayor, I would make his/her vote be worth more than 1. I think about 10 to 15 would be the right value - so Council as a whole would still be a significant force to oppose a rogue mayor. As an added bonus, I might add 4 aldermen, elected by the voters at the same election, for the 4 community council areas (Toronto/East York, Scarborough, North York, Etobicoke/York). The vote of each of the these aldermen would be worth about 3 to 5, depending on the population of the area.