Possible, since Shadowcaster (where that old gent is from) also contains enemies that are basically empty cloaks. The way they crumble when they die could serve as a base and a reference for a death animation here. Heavy sprite editing needed, though.
You really haven't done anything to remotely warrant the title of "HD" - it just has higher contrast (and more washed-out colors), more detailed abs (and his eyes are almost completely gone), and not a thing has been done to relieve the jagged outer edges.
I don't like HD Doom sprites at all to be quite honest. 99% of them are all just blurry crap. Sorry to sound harsh, but...well I'm frankly sick of seeing so many poorly done HD sprites.
Hell I don't even like the good ones because they never seem to match my idea of what they should look like. But I can appreciate the effort put into the ones that actually look good, like Mtzfire's for example, but I still think I'd just prefer to stick with the classic sprites.
I understand your POVs, but I said that I knew the result was not close to the base Imp anyways. I post it because I thinked that it may be a good base for an Imp Variant (as the majority are just recolors and\or franksteining or minor edits) With minor edits, that might be a good base to an new simple enemy to frag as seen below. (Corrected myself: I wanted to do HiRes, not HD (I'm not enough skilled for HD).)