To have a former-BB makes very good sense, because they are both now summer shows. To have a former-S might do some good, but it wouldn't be as cohesive of a tie-in since the shows haven't been on "together" in quite some time.
If they did put a former-S on TAR5, I guess I'd be indifferent. CBS does have three long-running (in reality genre) shows, and if they wanted to tie them all into a TAR season in some small way, more power to them. I'd probably be all abuzz if some former-TAR was going to be on either BB or S.
For those of you that think these former 'stars' take your place...unless you got at least called for a semi interview for TAR5 you weren't going to make the show anyway, whether there were 2 openings or 20 openings. That's reality, and I'm in that same boat with you. Now, if you did get to semis, or even made it to LA, then maybe "your spot" was "taken" by someone else. But, maybe not. Maybe you still wouldn't've made it. Maybe they interviewed 200 teams for semis, and you were #200 in their eyes, and had no real chance. Or maybe they brought 25 teams to LA, and you were #25. We just don't know, but for those of us that didn't even get called, we weren't really impacted at all.
Somewhere else I believe I've seen a screenshot from the preview that looks like it may be Alison's Donny. And, could the screenshot that everyone is all in a tizzy about it maybe being Survivor Kelly, could it just be Alison. To me, it looks at least sort of like her.