The big difference between Kmart and they guys you talked about is he is both often injured and has a bad attitude. More importantly Kmart is a max salary player. This makes the risk so much greater because if he doesnt work out then you know have committed a ton of money to him for the next five years or so. As for your claim that all it will take is Juwan and a pick, that does not work. There are rules to trade and salaries must match. Juwan makes under 7 million next year and Kmart makes 13 million. It just doesnt work without us adding at least two more players. We are far better off targeting Camby. They might have to get rid of him due to salary cap reasons. Yes it will be very hard to get him, but at least the Rox and Nuggets talked trade around the deadline, and Camby only makes about 8 million next year. A deal would probably have to include Juwan, Luther, JL3 or Vspan, and some picks, as well as other names to make salaries match but Camby next to Yao would be great.
There are degrees and variations of risk. It's not very smart to take your risks with max contract players with a strong history of injuries. The "safer" risks are in the draft, NBDL, EURO League, and players not making max $.