You brang the example - how does Miami played at the begining of the season and how at the end of it [exluding their finals... :+) ]
bad streaks happen, for a short second you didn't believe that you can not echange key parts and still be succesful.
Detroit and NY both get better after teh melo deal, to bring an example with an push even over a longer period. At least i never saw a manager sayng we had to keep all player, and beware of fresh blood. Normally they say they want to keep a core, a in negoations with all players and then bring in new blood.