Lotso is currently planned for sets 7596 (Trash Compactor Escape), 7599 (Garbage Truck Getaway), and 7789 (Lotso's Dump Truck). These will be the first time we've seen Lotso in minifigure form.
Minifigure Parts and Accessories
Lotso comes as one single piece with removeable arms. Video reviews from The Brick Show show that Lotso does have articulation in the shoulder.
Like several of the Toy Story 3 minifigures, Lotso appears to come in "clean" and "soiled variants". The "clean" variant appears with Lotso's Dump Truck (7789) while the "dirty" variant comes with the other two sets. The "dirty" variant also has a meaner expression on his face.
A cute little detail is that there is a printed tag on Lotso's bum, just to further establish he's a stuffed animal.
The only accessory seen with Lotso is his cane. That part seems to be represented by a 4L reddish brown bar.
Army Building Potential
I imagine the ABP for this figure is low to moderate. Unlike the army men, there appear to be no parts or accessories that would be sought after in multiples.
I think if a collector is seeking to fill out a LEGO Toy Story collection, then Lotso has appeal. Beyond this we will have to wait and see...
(Picture from Amazon.com)