I could go for a GI Joe scale figure, but there's no way I'd collect the whole set. A few examples of figures I'd want to see.

Circut Breaker
GB Blackrock
The Mechanic
Lord Zarak in Headmaster armour with removable helmet.
Centurion

The last two aren't really humans, but hey.

And while we are talking non humans, why not do a spin of series with re-imaginings of the Pretender shells as action figures? Sure they wouldn't hide TF's or transform, but who wouldn't want a poseable Bludgeon or Skullgrin pretender figure?