With all the rolling changes in the cloth torso construction and design it is now the new normal to take a look at the backside of the dolls to note any changes.
For my Tenney and Logan dolls it was not so much the construction or design of the torso that changed but for one doll, the fabric itself.
My Tenney doll, bought on debut day, features the familiar classic cloth torso with backside horizontal darts for a rounded firm shape. Her cloth is the familiar course weave.
My Logan doll, also bought on debut day, features the classic torso design with horizontal darts--but the fabric seems slightly different. The end of the dart (the furthest point from the vertical center seam) actually puckers and is more pointy with the new fabric and gives Logan's side-cheeks a less rounded shape and transition around the side.
Upon inspection, the Logan fabric seems slicker and closer to a polyester feel as well as potentially thinner though I make no claims on the comparative strength or longevity between the two fabrics. (Note the color variation in the two photos is more due to camera lighting issues.)
Most noticeable is that instead of the clearly defined cross-hatched weave of Tenney's torso (left) Logan's weave is much tighter.
I did a quick comparison between Tenney and one of my more recent dolls, Samantha who was bought in 2013. Tenney's fabric weave and weight matches my Samantha doll's torso fabric. Logan's fabric is something new.
Late addition: Several people on other boards are identifying the new fabric being used as polished cotton broadcloth which is what OG seems to use. Consensus is that this fabric is less durable.