I’m not going to try to argue with Bob, what he says is true to a point. But just how far do you go when it comes to adding all possible footprints you think you might need one day? The fewer parts you put on the board the less costly it is to respin if necessary. But my comment was mainly intended for Adam who already seems to have unused relays and transistor outputs. He has now run out of IO and is already suggesting he trade the Pi for a Beagle Bone Black to get more GPIO. I just thought it was time to draw the line.
As for J28, all it does is allow you to write protect your EEPROM. My suggestion was to provide an expansion connector in addition to the EEPROM. At a minimum this connector should include power (5V) and GND as well as the I2C bus. You could also include any unused GPIO pins from the Pi. You don’t need to populate either of the EEPROM or expansion connector until you need them, but the EEPROM is likely to cost less than a dollar anyway.
As for the current J28 it is not necessary just connect the WP pin to ground. Of course you can also leave it if you want.
Also, I think you should move/copy the EEPROM to the other I2C bus (pins 3,5) as I believe the bus on pins 27, 28 are intended to be used for an auto-configuration EEPROM. Again you can leave it on the schematic and add the footprint to your board just in case you want to add it some day. As I don’t use the Pi I can’t tell you what’s required to be in this EEPROM, but an EEPROM on the other bus (3,5) would be free for you to use for your own purposes.