i do not know how you train in striking, but for me, i can strike you with any number of attacks and won't over extend or lose my balance. if you practice with me, i can guarantee you that my shomen uchi is an attack. matter of fact, we trained with striking pads regularly to make sure folks feel the strike and the level of power driving behind it.
I think the point has been missed, the person you have replied to has basicaly said that Shomen isn't really a strike that you would use.
shomen is a strike that you would use in the dojo, but if you get in a proper scrap there are 100 other strikes that are better. A shomen is a simple simulation of downwards energy, and is fine for that, you may even do this really, really hard - fine. But if I had to strike someone for real there are better things to do. Don't translate the dojo to the real world, to do so missleads the students. Uderstand the difference between the two and teach accordingly.