I'm not sure how huge of a loss the clubs are. I've been dragged to them for years, and frankly, there isn't a club there that isn't outdone by some club or another in people's metropolitan hometowns.
PI has to adapt to the times -- Pleasure Island was designed at a time when adults went dancing. That doesn't happen anymore for the most part. Disney is keeping up with the times -- people have been demanding more dining and drinking establishments down at Downtown Disney for years, and major retail store sponsors aren't going to flock to a danceclub-laced area. I think the loss of a comedy club is probably something that will probably be rethought down the road, but the idea of a special place where people go party and dance is long gone, pretty much everywhere these days.
Personally, over the last 6 or 7 years or so, I've had no pleasurable memories of PI, except for having to pass through it to get from one side of DD to the other, and having dinner at Raglan Road and wondering why it was stuck on PI...it will be nice to have an entirely new DD area with restaurants and shops -- and fewer intoxicated 21 year olds.
I know the planned Hanes design-your-own-shirt store will probably be immensely popular, as will T-Rex when it opens. The large balloon that will eventually fly over DD (similar to the one at Disneyland Paris, which is quite cool) will also be nice to see (and much cooler than one might expect). And getting rid of that stale beer smell all over PI and redesigning and repainting will bring in more interest from restaurants and retailers.
One thing to recall -- DD is not only a draw for Disney folks anymore, but also a very popular place for Orlando locals to go shopping and dining and still feel the "disney magic." You can't underestimate that.
The entire DD idea came out when Disney needed a way to keep their resort guests busy after the park closed. As Extended Magical Hours kept the resort fans in the parks longer, they welcomed the Orlando community more than they ever had with specials, restaurant coupons distrubuted only to residents, and other marketing techniques. Over time, it has transformed itself in the mold of a lifestyle outdoor mall, and its what Disney needs to keep the money flowing there, just like all other retail establishments. It's not just for Disney guests anymore -- it's an Orlando-based retail/dining mall.
