I agree with your reasoning, MichaelMa, about David not wanting his new found friends and aquaintences being badgered by McGee. Something I've often contemplated. That is, how much badgering did McGee do to those who were known to be aquainted with the Hulk, and presumably would know his alter ego.

As for CSI: Miami using revisiting villans. This is a fairly old ploy of the series, as CSI: Las Vegas, the original series from which the others are spin off's of, had one particular returning villan for at least two seasons.