When I imagine the dock, for me it’s a thing I would like to have out of my view (under/behind the desk). Actually, more like a hub. Considering that, I wouldn’t mind to not have a GPU case at all. Many GPUs already have a kind of a “casing” that can even be cool looking, and having no case would lower costs and size. You could then integrate eGPU capabilites (a PCIe port and power connector) in the dock/hub while keeping it portable.
So I am imagining two scenarios:
A/B: Dock with GPU connector. Someone suggested this in another thread. Sorry, I can’t find it!
C/D: Dock with TB3 passthrough, so the eGPU module would be added either as an expansion module (C.) or as a fully separated dock (D). This last one is the most realistic and flexible scenario, I think.
As @mirv points out, when having an eGPU inserted, a more powerful external laptop-like power adapter (green cable) should be used. When not using the eGPU, the V’s adapter could be used instead.
I know this may look a bit crazy. Not everyone will want to have a GPU sticking out this way. But including the GPU in the dock itself makes even less sense to me: more cost, and either smaller GPU or a bulky, not portable dock. So in that case I’d rather go with a non-GPU dock with TB3 passthrough (+ DIY eGPU solution, which is option D), or just a regular eGPU case with some extra ports, and no dock at all.