Pilsen, I'm only too aware of this recession, which has pushed previous traders such as Linda at the pet shop and Mick at the White Wood Shop off the parade. No small reason was the costs of the premises themselves rising relentlessly regardless of local trading conditions, and this has to be a deterrent to potential new traders.
If we get a Sainsbury's, along with the undoubted benefits will come the likelihood of premises rentals and leases rising to match what Sainsbury's can afford, and we need to bear this in mind. I would want to be sure that traders such as Neroli and Jumping Bean along with the other food shops and newsagent would not suddenly find the cost of premises jumping as a result.
On the issue of bringing in business, look at Forest Hill. Even though it has had a big Sainsbury's there for a long time, which - according to the reasoning of other posters - should be bringing footfall to other shops, we've seen boom and bust in that shopping area for years regardless. All of this need to be thought through before spreading the welcome mat.