However, if Obama is her closest competitor (or adversary) for the nomination when the primaries hit, she cannot fundamentally take the chance of not picking him as VP and pissing off certain parts of the black community (see 1988).
Finally someone agrees with me! I've been saying this but everyone says it won't happen.
I agree that Obama would be a good running mate for Hillary, but not for the reasons you mention. Obama's main support base is white liberals, and black americans are split as to whether to support Hillary or Obama. There are also questions as to whether or not Obama is "black enough." By contrast, Jesse Jackson in 1988 had very strong support in the black community but very little if any support outside of it.