My number 1 thing for the next MBP is to stop making it so thin. It doesn't need to be thin, there are plenty of other Mac laptops that are thin. It can then have all the features buyers of a workstation class laptop (which Apple markets the MBP as), such as ports and decent key travel. There is no need when buying a workstation class laptop to have to carry dongles around. All of the ports a working professional needs should be there. Sure put some USB-C/TB3 ports, but also include USB-A sockets, an SD card reader, and Ethernet because there is more chance these will actually be used. I'd also like a matte screen option and up to 64GB RAM, like the Lenovo P51 and Dell Precision 7520.
Some of you will say things like 'hey don't need Ethernet, why should have to carry round the "extra weight" of this port'. Then don't. Apple already has you covered with plenty of thin laptops. Buy one of those. What Apple doesn't provide right now is choice. It's a thin laptop, with no ports, a keyboard with no travel and a glossy screen or nothing. Other than the cooling there was nothing wrong with the form factor of the 2010 MBP. I would have been happy for Apple to carry on with that, improve the speed and increase the storage and RAM limits. I don't need a flashy laptop, I just need it to work.