This thread has made me think quite hard
In my limited Aikido experience, I have found that ura versions of most techniques have taken longer to learn (which could lend support to Rob's reasoning that ura is "the highly refined product of the understanding you learned from the 'omote' version").
In addition, the time between the points when nage meets uke and when nage concludes the waza tends to be longer for an ura movement. Omote waza tends to be sharper and shorter.
And when in doubt, eg, a very large partner, I tend to do ura more naturally. Ikkyo omote, it seems to me, is very deep, as variable as irimi nage.
I completely agree with Raul's comment here... but then can I say that ura was originally meant for very strong attacks? The longer time interval for a lot of ura waza allows for greater energy dissipation. You would need this more often when uke attacks very hard.
Omote waza which tends to be sharper and shorter, seems easier when nage doesn't attack so hard. On the other hand, ura waza becomes MORE difficult when nage doesn't attack so hard.
Then again, can I argue that a REALLY SKILLED practitioner is equally at ease with omote and ura, irrespective of the strength of attack?
My ikkyo omote has undergone many revisions over the years as I try to absorb different styles and timings of doing this one technique. This year alone in my dojo we've done five or six different flavors taught by the various visiting shihan.
Raul, would you mind sharing with us your insights on ikkyo omote? Please.