Perhaps it was designed this way protect the engine from to many cold starts. As much as I would love to have the FE it wouldn't be worth the extra wear and tear on the ICE. Now, if a a person's trip wouldn't involve multiple starts, i.e., you could do it on battery alone, it would be a preferred design.

Ford might have designed it to have the ICE come on after the battery power's been used up (this would allow for short trips and possibly avoid the using the ICE). A problem they probably saw with this is that if your ICE is not starting until mid trip you don't know it's going to start until you are on the road....not exactly the best time to discover a mechanical problem.

06 FEH AWD Premium w/ Moonroof & NAV. Doggie gate, huskey liner.
99 Jeep XJ Classic 6"/31s