Applying shomen uchi ikkyo omote directly if uke attacks first is impossible. Tori must attack first. That point is fundamental, this the Founder's teaching:


Tori : Do a wide step on the side with your right foot, immediately strike your opponent's face with your right te-gatana (...)
Uke : Try to parry the strike with your right arm.
Three different movements must be done simultaneously:


If tori doesn't attack first, he can't get uke's rear imbalance, which is necessary for the rest of the movement.
That notion is difficult to admit for all those who were taught that Aikido was an art of defense. That's why it is worth reflecting without prejudice on the Founder's words:
One mustn't make a problem with such relative concepts such as good and bad.
In other words, if one wants to understand Aikido, that shouldn't be done from a moral point of view. Morals are a human creation which evolve throughout human history (and the regions of the world).
No moral system can give a true insight of the laws that govern the functioning of the Universe. Aikido which obeys these laws is also beyond moral interpretation.
Aikido is not a sport, it is a martial art which laws (takemusu) are in harmony with the laws of the universe. Studying them allows the practitioner to understand his place in the universe. Aikido was born in Iwama, O sensei achieved in that village the synthesis of tai jutsu, aiki ken and aiki jo.
The International Takemusu Aikido Federation (ITAF) brings to the practitioner the structure he needs in order to work as close as possible to the reality O sensei MU defined. The official national representations are the guarantee of a teaching faithful to the Founder's.
In modern Aikido, weapons are hardly taught, if taught at all. In O sensei's Aikido, on the contrary, aiki ken, aiki jo and tai jutsu are unified and form together a riai, a family of harmonious techniques stemming from one unique principle. Each techniques helps understand all the others.
Peace is a balance between a human being and the world around him. The true martial art's goal is not to become stronger than one's opponent but to find in that opponent a way to realize harmony. There is no enemy anymore as such, but an opportunity offered to reach unified ki.