Why is Bobby Brown a bum? The only knocks on him in the past have been defense and passing, and he appears to have improved in both areas, most dramatically in the passing, floor vision, and pacing areas. Is he Chris Paul? No. But as a third string PG with upside, we could do a whole lot worse.
That said, we should look at Aaron Brooks, Toure Murry, and others during camp as well. I cannot imagine even if we give Brown a guaranteed contract for more than just training camp now, that we cannot just waive him later anyway if we decide on someone else.
Also, until we sign Kenyon Martin and CJ Leslie (neither of which are guaranteed yet) we only have 10 roster spots locked down, so there is room for two PGs and three bigs still. Assuming we do sign both, then one PG and two bigs makes more sense, but is not required.