How many Japanese sensei's exactly have you noticed that abstain from Group practice?
I've trained with no less then 7 in seminars and such, and all used it when the occassion makes it necessary.
However, I have heard that Aikikai hombu is quite crowded at times and that usually its partner2 practice and no group practice. The trick is to learn where to throw as nage, and control your uke enough to throw him close to you and as uke, to learn how to fall within 1 tatami mat confinement and get up fast!
Needless to say, breakfalls are not recommended.