From what everyone has said so far it is currently not busy and that is why Disney has mulled the idea of opening it up (or maybe it is just us here).
But isn't it not crowded mostly due to the fact that the resort has not sold out? I thought DVC could only rent on points the percentage of the resort that has been sold.
If the resort is only 50% then max, only 50% of the rooms could be used by DVC and the rest cash via CRO. If cash customers are not eligible, it is highly unlikely that the lounge will ever fill to capacity until the resort gets closer to being sold out.
Or am I not understanding how this works?
BTW, can't wait to check it out in 96 days!
For the most part, yes that is correct. And for that reason alone I would be surprised if they make changes before BLT is fully sold to members. With the resort only being open 3-4 months it's difficult to predict how crowds will change a seasons change and the volume of DVC guests grows.
Also my money is still on a second Contemporary tower as the next WDW based DVC. If so, that would be the next logical group to gain access.
Expanding access to other DVC members on-site would be a huge switch. I'm not convinced that crowds would skyrocket simply because it's a long way to travel for most...and the MK is right next door. If you're going that far, why not walk another 5 minutes and be inside the MK or Wishes.

I'm sure some would try the lounge but far-and-away more people would just to into the park itself. (IMO.)
The lounge and outside deck are designed to accommodate something like 400-500 people. And from what I've heard the smallish lounge itself is rarely full these days, much less the deck. Before the lounge opened there was a lot of speculation about overcrowding and guests being turned away. As it turned out, the facility is at 10-15% of capacity most nights.
I think it's inevitable that admittance will be expanded somehow--it's more a question of how and when. What they don't want to do is allow access to all DVC members staying on-site, and then have to remove that "perk" if crowds prove to be too large. But I personally don't think they would be. People aren't going to flock over in massive numbers from other resorts.
Whatever they do, I wouldn't count on BLT guests necessarily getting much of a priority. They certainly won't do anything that would require additional manpower to administer. If the lounge opens at 5pm, they may (for example) establish that only BLT guests can enter from 5-6pm and then begin admitting all others after 6pm. But they aren't going to start taking ADRs for the lounge or anything along those lines. That would add thousands of dollars of expenses for CM time, computer resources, telephone lines, etc.