Cryengine 3 is for games that look realistic. Nearly every feature of Cryengine would be wasted in Blockland.
The contrast between realism and blocko would be even worse than it was before v21.
Plus, if you want Dynamic Physics, that would DRASTICALLY increase the time it takes to make a vehicle. This will make it far more difficult to make add-ons and deter people that are not already great at doing stuff like that. (>> Yndaaa, for instance).
Like, imagine how silly a Blockhead looks in g-mod. Then imagine that, except it's not supposed to be a joke.
Not only is it not going to happen, it's something that you don't want to happen. Like Brian said earlier, it's going to be a stuffstorm for modders.