Atl, and Mia. Cle and GS also very close to Miami's number of missed games. After them comes Bos, with Por, Sac, OKC, and Det checking in before Denver.
Most wins lost due to injury (as of last week): Brooklyn, Atlanta, Philly, NYK, Boston. After Boston, the next teams are Washington, Portland, Philly, Lakers. Denver will obviously move up that list now that Murray is out.
I don't know for sure if this year has seen more injuries, or more significant injuries, than previous years. I don't think we've seen so far that the conference finals teams from last year have been put at a significant disadvantage as compared to the rest of the league.