MacBook is a pretty great device, and I don't think it makes sense to revamp the product in it's second year. The coolest update is another new trackpad, this time with Touch ID. Also, there's a new option to have a built in cellular antenna which uses an Apple SIM just like the iPad.
On the technology side, the USB-C port gets an update to support Thunderbolt 3 as well. Typical processor and graphics updates along with a Bluetooth update to 4.2.
MacBook Air won't get a revamp either, but that's because this device is on it's way out the door, getting replaced with the (even airier than the Air) MacBook. So just technology updates. All USB 3 and Thunderbolt 2 ports are removed, being replaced by 3 USB-C + Thunderbolt 3 ports. The processors, graphics, and Bluetooth antenna also get an update.
I think it would actually make sense for MacBook Pro's design to get a bit of a refresh. The current design is still based on the unibody design that was established 8 years ago. Next year, the notebook will have had the exact same design for 4 years. So making it a bit thinner and lighter would be great, and there's a few new things that the MacBook is doing that could easily be brought to the MacBook Pro. The thinner keyboard, the tapered battery, new aluminium color options, and a more energy-efficient Retina display with larger pixel apertures. Like the MacBook, the Pro would also get a Touch ID trackpad.
And of course the regular technology updates. All USB 3 and Thunderbolt 2 ports would be removed. Three USB-C + Thunderbolt 3 ports would take their place. Two on the left side and one on the right. The processor, graphics, and Bluetooth antenna would also be updated. The graphics and USB-C + Thunderbolt 3 port mean that MacBook Pro now supports an external 5K display.
With the non-retina 27" iMac out the window comes the introduction of the 21.5-inch iMac with Retina display. But other than that, these computers are fine, only needing new technology. Getting any Mac with a HDD should no longer be possible, so a Fusion drive or SSD are the only options available. Also new processors, graphics, and Bluetooth connection upgraded to 4.2.
Mac Pro has a long road ahead of it. At this stop on the road, it's just getting technology updates. All USB 3 and Thunderbolt 2 ports are removed, being replaced with 8 USB-C + Thunderbolt 3 ports. The processors, graphics, and Bluetooth antenna should also be updated.
Much like the Mac Pro, the Mini's design has a long life ahead of it, so there isn't much of a need to redesign it at this point. It'll get the same 'no HDDs allowed' rule as the iMac. So just SSDs and Fusion Drives. The USB 3 and Thunderbolt 2 ports are removed, being replaced by 5 USD-C + Thunderbolt 3 ports. With a new processor, graphics card, and Bluetooth antenna, it should also support an external retina 5K display.
Apple Retina 5K Display
- Retina 5K resolution
- Built-in FaceTime HD camera with microphone
- Built-in 2.1 speaker system
- Detachable MagSafe 2 cable
- Detachable USB C + Thunderbolt 3 cable
- USB-C + Thunderbolt 3 input (x4)
- HDMI 2.0 input
- 3.5-mm stereo headphone minijack
- Gigabit Ethernet
- Similar industrial design to the iMac
Magic Trackpad + Magic Mouse
These interfaces get some nice updates including an integration of Touch ID into the surface of the trackpad and the top of the mouse. The batteries should be integrated, allowing for much longer battery life. Just like the Siri Remote, charging would happen via a Lightening cable. Also to increase both battery life and connection strength, the devices would be updated to Bluetooth 4.2.
In El Capitan, Apple added some surprising new frameworks to help developers make gaming on the Mac a little better. So while gaming isn't a core strength of Apple's, I don't think they dislike it by any means. There has been documentation for developers to support game controllers on iOS and OS X for a little while now, so I think it only makes sense for Apple to put it's hat in the ring. The controller would support an accelerometer and gyroscope. It would have an integrated battery, being charged via a lightening cable. With Bluetooth 4.2, battery life would be great as well.