Two quick and dirty observations:
1. the advancement line of the thing has been messed up some real bad; it implies that the thing has either 2 HD (contradicted by the entire rest of the statblock), or advances to Large at 5 HD (somehow skipping Medium it would have had if advanced to 3 or 4 HD, which ot already has (this makes an equal amount of sense in the original context)); and
2. more importantly, the descriptive text specifies that when inside a host, it will commonly steal fresh clothing and dress itself, meaning that it can use the preexisting prehensile limbs of the host creature for manipulation of objects that requires better fine motor skills than swinging a sword.

Two other even quicker and diriter observations:
a. the fluff text says it can detect a fresh corpse from a mile away; that's an odd thing to not make an ability like the Shark's Keen Scent, but hey, it's kinda there;
b. while the text says it can only wear a given corpse for a month, it further clarifies that's because it's too lazy not too eat something else instead. Might mean it can wear a good body indefinitely.

IN more general terms, +6 DEX and +10 CON is crazy good. DR 2/– at 4 HD is nothing to sneeze at either, and certainly better than some Small-size level NA. With some good advancement options, I can really see a positive LA here.