Aikido is extremely effective, but its goal is not winning a fight, but to protect against an opponent. You are just using the same limited measure (winning a competitive combat) for all martial arts.
Seriously, if any of the ideas were at all helpful in real fights, they would be borrowed by other martial arts. But they aren't and haven't been.
Aikido is excellent form of exercise and entertainment which might help you when faced with someone with no training at all. Thinking of it as anything else could be a dangerous mistake.
This is true of any martial art, when not on a MMA environment.
> You simply won't react fast enough, their reactions won't match your expectations, and (very importantly) the first solid hit they get on you will leave you in shock because your body is not used to it.
Again, nothing new here. If you are only practicing limited maneuvers, no martial art is of any advantage. True Aikido masters know how to handle the unexpected.
> Seriously, if any of the ideas were at all helpful in real fights, they would be borrowed by other martial arts
They have been, but I agree that they are not an advantage when you want to win a frontal combat. That is why the martial arts mentioned above are considered the "winners".