I'm going to skip over the part where this was already mentioned/discussed before (
https://forums.macrumors.com/threads/904112/).
IMO, I don't see the point of a slider case for the iPad. Maybe i'm missing something, but my understanding of a slider case is a 2-piece case that gives you access to the port when separated, and protection when not.
It seems to me that other companies agree with the need to access the port for dock accessories, but have decided to do away with a 2-piece approach. There Speck CandyShell, Incipio Feather, Switcheasy Nude, and Hard Candy Kickstand are just a few examples of cases that are one single complete case and still have access to the port for docking accessories. I know a few may argue that the Nude and Feather don't provide as much protection, and the Candshell and Kickstand have moving parts.
To me, the idea of moving a chunk of the bottom protector off just to access the port is a bit much, and is multiplied in respect with the iPad. From the pictures, the protection value looks similar to that of the CandyShell. The SGP slider does not provide enough protection value to make up for the hassle of a large removable piece.
I think it's still debatable that this was a good idea on the iPhone/iPod Touch to begin with. It just seems to me that someone felt that since this was popular for those devices then it will be on the iPad. I know the iPad is young, but I think or hope people were realize that not everything thats "good" for the iPhone is good for the iPad.