Jessmke, the majority of pockets are actually a trim option compared to prefolds or some flat folds. They're deconstructable all-in-ones: thick soaker/insert in the middle, two layers (PUL and fleece/suede lining) in the wings. Prefolds are usually 4x6x4 or 4x8x4 which means there are 4 layers coming from the "wing" being held against 6-16 layers from the front. In the most common fold where the front is doubled over and the wing brought around on top there are 12 layers at the hip!!! That is THICK! it's okay on a 20lb+ baby but on 6lbs? Ugh.
I liked origami fold for flats, fewer layers in the wings, actually bought bigger real flats to keep using that fold. When she was tiny we used "flour sack towels" as flats, with bamboo washcloth folded inside as an insert. Very cheap compared to "real" diapers and just as effective!
Marie, I haven't tried AIO on a newborn but her prefolds were only ever wet in the front and middle. Nothing like how drenched they were from 9m+, when all the way up the butt and even the wings were soaked.
Re: mobility, my daughter rolled over for the first time the first time she was down on the floor in a disposable, at 2.5 months old, and she only rolled naked or in a "sposie" for a month after that. But she also had minor hip dysplasia when she was born and the specialist said the cloth bulk would help her hips. She hit later milestones like crawling/walking just fine in her prefolds but I could tell they impeded her a bit (waddling), they also cushioned her butt when she fell
I used the bikini fold a lot when she started standing and walking, it was a very compact option and trim in the crotch (but hard and stiff -- couldn't have been comfy)
I have thought ahead to #2's diapering past 6 months but haven't picked -- trying to choose between fitteds and big flats. I already have a whole stash of prefolds I planned to re-use so I have to learn to see if I want fitteds! Don't have a good excuse to buy a new stash when I want to learn! Especially because I want/need to use bamboo and hemp for them, not plain cotton. Oh and definitely using woolies & pull on PUL for covers at 6m+
At some ages pants fit properly and at other ages I had to size up.
the prefold that I bought is large size so maybe that is the reason I'm having trouble. Now I don't know in what I'm going to use this large prefold. 
