Re: direct, literal reincarnation, my sense of the reason why it's much more rare than the new Disk mixes type, is because these human Earth lives are no walk in the park. For Souls whom have directly experienced it, I think often after a life finishes, we are like, "Whoo, glad that's out of the way. Yeah, not doing THAT again anytime soon." There are of course exceptions. Some of the very immature Souls cycle in and out fairly often, because they are addicted to the stimulus and action here. Being low on empathy, sensitivity, and high on power/control issues, human experiences don't phase them much.
Cayce's guidance once said something like, the longer the time spent between lives, often the more spiritually evolved the Soul. Not as a hard and fast rule, but as a general trend/average.
However...just like there has been an increase of ET Souls incarnating here of late, I get the sense that there is a higher percentage of repeaters here than normal as well.
And a percentage of the ET Souls are ones that had a human experience before they graduated out of this system, and now are coming back. In these, often Arcturus the Star is strong in a special kind of astrological chart delineation.
The reason for the above two trends is because Souls with such experience/background, have a higher probable potential of handling their new Earth lives better than the average, and gaining more complete control over their bucking bronco human animal bodies.
Since this is such a critical time in the human history, Expanded Guidance has been sending in some of the best and brightest helpers there are. Ones that are very strong, and very attuned to the Light within. Things are truly critical in this cycle. There is still the potential/possibility for going either way--great and rapid collective growth, or even much worse collective stuckness and extreme suffering (this is why promotion of vacation type beliefs really bother me).
Plenty of even older type Souls have had trouble with one or more aspects of their bodies and Earth life. Take Bob Monroe for example, definitely an older Soul but he didn't have a whole lot of discipline when it came to his diet or the health of his body. His Disk self level in cahoots with his body had to basically try to force him to treat his body better, and even then he had a hard time of it. He was stubborn and didn't want to see the need for change and discipline. Not even after "Ah So" sternly talked to him and Rosie about this issue.
The health/balance of the body is part of the package deal of consciousness expression here. If the body get's too imbalanced, it creates gunk between the flow one's consciousness and the attunement and/or expression of same through the body in the physical world.
Attuning to one's expanded self and expanded guidance is a very holistic process that involves the physical, mental, and spiritual aspects of the human energy system. Repeaters, especially ones coming in with both human and ET direct experience, often know this better than most from the get go.
For an example, most of the just previously ET Souls I've met, are towards the vegetarian, vegan, or pescatarian in diet. Not all, but most.
By "ET", I don't necessarily mean experiences in running around in little grey bodies or the like. Some of these systems and experiences are in completely mental/nonphysical levels which are not body based. In these, your unique individuality IS your body in a sense.