1. Use of glue somewhere which knackers any chance of repairing it. Memory, disks and that is it.
2. Proprietary fan which will get noisy after time and cost a fortune to replace. First step will be to put it on the floor so you can't hear it... leading to...
2a. Someone is going to put a half drank coffee cup in it and blow it up.
2b. Plume of hairballs every time a cat owner fires it up as it'll suck in every bit of crap off the floor (the dirtiest place in your house).
2c. Someone will whack their noggin on the desk while they're trying to plug their headphones into it.
Perhaps I'm bitter because my 2010 MBP blew up spectacularly, but I'm seeing a lot of visual design over sensible engineering in Apple recently.
The iMac is a sensible design over this. If only it wasn't such a bastard to get inside it.
I tend to use computers for years (typing this on a 7 year old Lenovo). I'd like the opportunity not to fill up a landfill after a couple of years.