The concerns have to do with what sort of coverage you will have under the new policy. Most people in Ontario have 1 million in coverage, which sounds like a lot. For most accidents with minor injuries this should be sufficient but if you could major injuries to someone else, for example, then you are on the hook for everything over 1 million.
Think about your own financial situation. If you are hurt and cannot work again how much would you need. For most people, 1 million over a lifetime is nowhere close to enough.