That is a major problem. The province would also need to achieve goals to keep themselves in power. With an independent Toronto (GTA), there would only be one level of government thus combining provincial and municipal elections into one. The Toronto council would be replaced with MPPs. The rest of Ontario can have a proper government the focus on rural and Northern Ontario issues.
There has been major divides between rural and urban Ontario, such as the sex ed issue. If GTA is separated from the rest of Ontario, they can have separated education curriculum as the "two" provinces can do their own things. Other ministries like health care, energy, MTO (highway design, expansion) and OPP could operate over the two jurisdiction if that benefits both through agreements.
That fact that many well known cities around the world have federal level cities, maybe it's time for a change. Especially after Ford thought he is the Premier of Toronto.