Honestly, Fabuland is overdue for a relaunch.
Minidolls were successful, another scale would not only add realism to models and could also rejuvenate stale product licences (like Starwars).
Technic Scale Figs would also be pretty cool, although not all technic models are at the same scale.
Duplo is the right proportion.
Fabuland scale would have been ideal for the 4+.
Honestly, Fabuland is overdue for a relaunch. Minidolls were successful, another scale would not only add realism to models and could also rejuvenate stale product licences (like Starwars).
Technic Scale Figs would also be pretty cool, although not all technic models are at the same scale.