Sbtb, has had a huge following over the years, and would be easy to do on the cheap, so no surprise their. Punky Brewster didn't really do much in syndication after the show was over, but, America has fond memories and the original actress wants to do it, another cheap show, smart for nbc. AP Bio, NBC tried 2years, never could make it a hit, but is said to have strong web presence.
Being that all 4 are IP's with different degrees of web precence, I would think Sliders could have a chance of a rebirth, no idea if ownership issues would make it more complicated, but looks like they are leaning heavily on nastalgia for old owned IP's which is smart at launch because potential customers will be driven to pick up stuff they remember fondly.
I would say if we want Sliders sooner vs later, we'll have to hope this strategy works, if old ip's sell the service they will look for others to win the war, if not then we'll have to wait for the next wave