That's one thing I also forgot to bring up in my initial post. Han and Chewie have actually been together for closer to 50 years, which makes this moment even more implausible. Let's face it: like the trash compactor reference, it was just another cheap joke Abrams put into this movie.
Frankly, most of this could've all been easily cleared up if Lucas knew in advance when making IV that he'd also be able to make V and VI right after that... and would also eventually make I-III. Let's not forget Luke and Leia were never twin siblings until work began on the script for ROTJ... and that the original Death Star was also not supposed to be complete and fully operational until ROTJ as well (which is why a second one was being built in the final movie). Some people also claim Vader was never originally supposed to be Luke's father, but that would make the fact that 'vader' means 'father' in Dutch one of the biggest coincidences of all time. Given Owen's crusty demeanor, I have no problem believing he'd let Luke know that he and Beru weren't his parents.
Apart from the emergency stop there in TPM, Anakin's covert return there to see his mother, and the Empire going there only because Leia's ship was going there (because that's where Obi-Wan was), Tatooine hasn't had that much more significance in the grand scheme of things -- just like Hobbits aren't that significant in Tolkien's Middle-Earth history outside of The Hobbit and LOTR (the latter only ever being written because his publishers wanted another Hobbit-centric work). Because SW is also by and large a family soap opera, and because the Skywalker family originated there, it should stand to reason Tatooine have a significant place in this one story Lucas is telling within a much larger universe.