I seriously doubt if the GECK will be coming to consoles.
To start with, the GECK (and Creation Kit) has always been a prettied up version of Bethesda's in-house tool. It's designed for professional quest and location builders to place content fast, both to a design template and (when that's too restrictive) in a more freeform manner. To keep anything like a commercial production pace it has to be a full mouse/keyboard/windowed setup.
To put something on consoles they'd have to create an entirely new product from scratch. And I suspect it could only be used with a limited subset of art assets with clearly defined snap-together design. Plus it would need an entirely different interface design for everything, including defining dialogue, AI routines and NPC setup. There'd also, as mentioned above, be the problem of scripts, which could easily render a game unplayable and a savegame irreparably corrupt. Bethesda's games have always used scripting heavily, and I suspect Fallout 4 will follow Skyrim by using it very heavily, even in straightforward dialogue and quests.
So, would they really invest a lot of money and manpower developing a toolset that could only (realistically) be used to put locations together with no quests or dialogue attached? Or would they invest that money and manpower in their next game?
Whether mods themselves would be allowed on console is something that's much more likely (however unlikely), but probably only simple mods that could be thoroughly tested, anolysed and certified DLC-level safe by Bethesda, without them spending stupid amounts of effort doing so.