But - it is still possible to use an sdcard even with the older nexus 7. Here's how. Using Stickmount, the proper cable and an inexpensive card reader.
Stickmount is designed to read a flash stick drive, but it will read a sdcard just as well in a card reader. I do it all the time. Not as convenient as a built in slot, but with a short 8 inch cable almost as good. :-)