I care. When DH and I bought 5 years ago we were younger (going from 25 to 30 really is a BIG change) and took "value" trips -- cheap food, commando style park time and small rooms for as long as we could get them. We chose OKW because it was the cheapest price (and barely got by, even with a CM discount) and less points per night to stay. It didn't matter if we could stay at another resort -- we were never at the resort.
That said, we've grown up a lot in that five years. Better jobs meant we could add on to our points (at OKW with the same use year because it's easier to plan trips that way, especially in case we ever want a grand villa, etc.). We like the one-bedrooms because we spend more time in the room -- even if it means a shorter stay -- and we love to splurge on room service for breakfast. We spend time at the pools and OKW's pools are boring in our opinion (though that may change -- and I understand others disagree). I also like to workout everyday and the workout rooms at VWL and BWV are much nicer than OKW. So we frequently stay at VWL, enjoyed BWV in January for the first time and hope to stay at BCV in May (have to plan our February 2005 trip first and then see what points we have left for "upgrade" from OKW).
I for one, would be quite unhappy if they stopped allowing us to stay at other DVCs -- unhappy enough that I'd think about selling (we'd make a huge profit given what we bought it for!), or frequently rent out our points to get cash to stay where we want.
But I don't see that happening. They'd get too many complaints and a lot of bad publicity. And so far, the system seems to work fine the way it is.