The 3.5mm socket is fine, in it's place. When you have a huge amount of front panel real estate to play with, you don't even need to limit yourself to that. You can go the whole ¼" hog, and why not? The tech is 100 years old and is well supported.
However, as Apple made clear, it's time to move on. The size of the 3.5mm socket, particularly when one considers how limited the thing actually is, means it really is time the thing went. Sure, it has been convenient, but so were a lot more things that have come and gone. Even Apple's laptops double up the 3.5mm socket with a digital i/o port. In electronic terms, the thing is huge and creates major problems when attempting a sleek design.
Future phones will probably get rid of all wired i/o ports. Charging can already be done wirelessly. So can data transfer of all kinds. I'm prepared to bet the Lightning port will not last as long as the 3.5mm port did.
