Add another 3 years to the counter... with "Epic" being "re"released I do not see Battlefleet Gothic coming back anytime soon, especially since the reboot of WFB has still not made it out of development yet for some reason.
And now with the endemic GW scale drift officially moving Legions Imperialis up to 8mm, the real question is would BFG actually come back or would it be a BFI* instead?
Now there is no historic crossover GW game that could force a change in BFG as opposed to the new Adeptus Titanicus and Aeronautica Imperialis which both pulled traditional Epic to a different scale for compatibility's sake**, so any change would be arbitrary. The ship scale should not matter given the original post to post measurements, but would GW keep the same decades old flying bases, or introduce a new basing system or even consoles like in AT? All the bases are changing in the new Epic, so I think any new BFG version we see would not be compatible at all with anything prior as far as bases, and probably not in playstyle either as larger bases would preclude any large masses of smaller ships... goodbye 25 Brute Rams...
My predictions for 3-7 years from now:
Different ship bases, but not multi-bases
Less ships on the field, but much larger models
Radically different ordnance markers, if any
*I = G x 125% in the Nottingham alphabet
**Totally not for any other reason at all