EB, your idea has possibilities. There’s a subway station on St.Helen’s Island. Building a stadium there would definitely be better that the current Olympic Stadium. It would be more centrally located, thus more accessible to Montrealers. The only issue is the bridge factor. Currently, the Island is only accessible via the Jacques Cartier bridge and perhaps also the Concord bridge. Not sure to what extent access to the Concord bridge would be available.
So if access to the Jacques Cartier bridge were to be cut off due to fireworks or other events or incidents, then access to the stadium would pretty much be off limits. Entire games could get delayed or cancelled because of a multi-lane accident on the bridge which would paralyze the entire bridge. If there were multiple ways to access the Island, then it would be an ideal location to build the ball stadium. Otherwise, the only feasible solution is the downtown area. MLB has said repeatedly that a downtown stadium is essential in order for Montreal to get a team, yet no one has come up with a solution. Why waste effort and money promoting a return of MLB baseball to Montreal when no one has proposed a site located downtown near a subway station. It makes no sense, no need to waste any more money till a downtown site has been secured.