Given that he supposedly cracked secure computers, which I would hope was no simple matter, the US shouldn't be extraditing him to face prison. They should give him a job.
https://en.wikipedia.org/wiki/Gary_McKinnon#Statements_to_th...
Apart from the normal reasons you don't hire thieves to guard your stuff[1], he is too mentally unstable to be trusted with anything. Remember, it was his mental instability that probably saved him from extradition.
[1] Yeah, it makes for great Hollywood stuff, but that's Hollywood.