I just want to say that the only way the armbar is possible is if your opponent doesn't contract both pecs. This is what mostly happens when a match starts.
Only in aikido7 you can do the armbar since the opponent cannot grab the other shoulder.
The chance of landing an armbar is quite low in the regular aikido mods.
I have saved all bjj related things off Aquitas replay thread and saw that in most of his armbar replays, the opponent either spaces or doesn't contract both wrists.
What's also a problem is ghosting.