I felt this story was slightly hackneyed. The term "predictable" definitely fits here, but I mean the term to show that the mystery of a ghost story--the sense of atmosphere--was lost via this predictability; it was campy.
The themes of this story--themes of robbery--link, in my mind, with Colonialism. The Indian doctor in question was, after all, an Englishman who doctored in India, presumably under British rule. That this doctor would take the hand of his Indian patient--take it on promise to return it--and fail to keep that promise (via an accident) is interesting; that another brown man's death and amputation would allow for the spirit to disappear is also fairly intriguing along those lines. These themes are perhaps unintentional--the whole contrivance of the wrong hand given, for example, pretty clearly indicates a more lurid design by Doyle; however, his positioning of the Indian man as something ghostly and (in a sense) lesser in England, and nevertheless the interminable need to appease him before he rests and allows the wealth to spread (to our landed narrator) has some fun implications. It's not real implications, perhaps--it's just reading too far into it, I think, in this case--but I fear that it's still jostling the box about.
Some of the imagery in this tale is marvelous. The wall of grotesqueries goes along quite well with the narrative--these are the after-images of suffering preserved, obviously something evocative of spirits and afterlife; it's a bit of irony that the real brown hand was destroyed, whilst these others weren't.