I agree, the original arc troopers left a little to be desired. I mean, they were cool...but the sculpt was a little off and articulation was limited.
Good news though....Hasbro actually DID re-sculpt this figure for the 30th anniversary line! In one of the current comic-book 2-packs, you can get Obi-Wan Kenobi and Alpha (an ARC Trooper). Alpha is a brand new sculpt, with super-articulation and a removeable helmet. You might be able to find this at Target or Walmart. They came out shortly before Christmas.
Also, not sure, but I think the Entertainment Earth Republic Forces figure sets come with 2 "Shadow ARCs", which are black and red ARC troopers....I think they have a newer sculpt. Not certain, I haven't picked them up yet.