The 2.0 duratec is a very very near square setup which is optimal for a forced induction setup. Whereas the 2.3 (and 2.5 which is even worse), is out of square, because it's a "stroker" version of the 2.0 liter, meaning the rods have to be longer, which simultaneously give those engines more power and more torque... at the cost of a weaker rod and crank setup.
Boosting a 2.0 liter engine in our cars has always been next to impossible 100% because no one does it, rather.. not enough people in the community were willing to give back if they did do it. No one properly made tunes for the car, and a tune is KEY for a good turbo setup, not for the sake of power, but for the sake of actually being able to trust the engine.
It was indeed ECU related troubles that just made it a bit more difficult to talk to the car vs the well cracked 2.3L
But again it does indeed go back to the fact that so few people did it. My local that blew up his 2.0 liter turbo a few years ago never had a proper tune and could never get any help (a shop could've done it, but he just needed something safe, not trying to put down a lot of power with stock internals, especially when at only I think 6psi). So seriously it is more of the community at blame than anything else.
At this point typically the "well you should've bought a MS3" comes into play. While this may work for the 2.3L hatchback owners, it does not work for those with sedans that love sedans, and it also doesn't work as well with the 2.0L guys, because the base model 3 costs so much less than a MS3, you can fully properly low PSI boost a 2.0L and have it tuned for less than the cost of a Speed3, and likely have less issues that the Speed3 has (did you know that OUR timing chains are stronger than the MS3's? Seems a bit weird, but I recently discovered through a MZR tech that the MS3 timing chain is often taken off and replaced with ours).
So in the end.. point your finger at all of us (rather.. all 2.0L sedan owners), and blame them, because they are the ones why we don't know as much about the engine, because not enough people did it.
Where we had upwards of 100 2.3L owners turboing their cars at the same time and continuing to learn, there were less than 20 2.0L guys learning at the same time, with everything being for the most part very different, so they couldn't exactly keep in touch with the 2.3L guys because it was so different.
Edit - keep in mind my response is from the old 2.0L duratec. NOT the Skyactiv 2.0L, which is very different. The internals cannot handle the boost, that's why no one has done it.