Gigabyte (via subsidiary Aorus) has released a Thunderbolt 3 external graphics dock that is specifically designed around miniaturized desktop GPUs. Additionally, the US$599 dock beats the competition in coming with a GTX 1070 pre-installed.
https://www.notebookcheck.net/Aorus-releases-compact-eGPU-complete-with-a-mini-GTX-1070.224998.0.html
I suppose if you keep your eGPU dock at home and don't transport it anywhere then you're not really gonna care how big it is, so you'd probably want to go with a larger dock & larger card so that the cooling will be more effective (and therefore increased performance). However, if you're the person that often wants to transport their eGPU dock then this would be excellent! I wonder how most people use their eGPU docks?