How mod-able is AOE3:DE going to be?

As per Microsoft, AOE3:DE is going to support mods. How much mod-able is it going to be? Will it be like AOEDE, supporting only single player and multiple-player scenarios? or, more like AOE2:DE, with more in-depth mods, like units/buildings skins, custom campaigns/scenarios, tech mods etc? I never got any invitation for AOE3:DE beta, so just curious.

It remains unclear, no mod support was showcased in the beta.