One of the discussed ideas for replacing the Dome is building around it and then knocking it down, which I don't know how you do on such a small, landlocked area.
Frankly, I'd like to choose a location like the Giants have on the waterfront, but that can also be like the Astros stadium with a lot of open glass to let natural light in inclement weather.
One idea could be to have it be where Ontario Place used be. That place has suffered a long decline, and I know there has been talk about what to do with it, and I think it would also end up being closer to the Baseball Hall of Fame.