And thats very understandable as well. Simple solutions. I think solutions are fairly simple however people just want to see if they can incorporate other devices and features into others that may or may not complicate things more than keep things simple. Ya, USB drive Mfrs make it so you need the drive connected directly to a PC. That's pretty much been the norm for a while and I don't see it changing. Sizes are just a minor issue. Drives are not that expensive either so getting into a 500Gb drive would be cheap and easily set up for your media needs if you still wanted to go that route. Ya, it's easy to see the USB 3.0 connection and thinking how nice it would be to take advantage of that and you still can. Just need to set your drive size goal to match that D-Link support and you'll be ok. Backups are another thing and I wouldn't fully trust my backups to USB. I mainly use backups over LAN for better performance and stability. Especially for large backups.
Good Luck.