Getting back onto the topic, I just want to chime in with Anne Marie and Mike (but don't tell them I agreed with them, they may not let me live it down). Some dojos are more energetic than others. Some AiKiDoka are more energetic than others. I remember being awestruck when I went to a Tai Chi gashgo once because of the number of disabled people and very old people who could participate and were made to feel welcome. Mind you, the style of Tai Chi that I practiced was quite 'martial' and involved a lot of pairing up and performing techniques that many of us would recognize in addition to the inevitable long kata. I thought that it was a shame that AiKiDo can feel so normative in what it expects from someone's body and their reflexes and their fitness. It has happened to me a number of times that the dojo where I practice has had students who had clear motor control issues. This was very challenging. Working with them was rarely fun and often simply unpleasant. Still, I treated it (and most of us treated it) as a learning experience that is part of our AiKiDo. I don't see why a sluggard is any different. AiKiDo is about taking what comes and working with what you have, I think.
Mind you, I do understand the frustration. That's easy to sympathize and identify with.