I think Denver's starting 5 are pretty much set Ty, AAA, Gallo, Faried & McGee (assuming they resign him). So I dont think Denver will be adding any stars in FA, but rather role players. The positions that need improvement off the bench are PG, PF and SG (pure shooter).
I think last season the lack of rebounds at PF when Faried was off the court was evident and alarming. So they need a good rebounder to back up the Manimal. This would only be the case against teams that are able to slow the tempo.