Jorvik is tough on Aiki for his own reasons.
I have my own theories about Aiki; but I think the same issues apply to all these arts: Realistic training driven by sound concepts and a sound training progression sets the stage for the individual's growth, the teacher guides and the student trains – a complex animal with many, many variables that can effect the level of success. In cases of “failure of training” if one can identify it, will no doubt be due to many levels of breakdown in this complex relationship of combative training.
IMO throws are throws, locks are locks, breaks are breaks, atemi is atemi, leverage and structure are same, Ju or changing is changing, they come in different flavors but they are what they are. Styles and systems are about how you train to do develop these skills and they all teach a part of this larger picture, some wide, some narrow, some unique, some exclusive, some inclusive.
General effectiveness IMHO is about who and how you train these different skills and how far you want to take them. There is NO one right way, just as there is no one right way to season all food, still most foods are cooked, and MA skills must be as well, some like it more well done than others.
Regardless of the methods these ideas and the concepts that drive them are real and do work. Yes some more/better than others under different circumstances, and yes differently for different people with varying levels of success; but it's all good - now whether a person is good, that is another matter.