Why didn't Dooku use Force lightning on Anakin or Obi-Wan on his final duel on the Invisible Hand? Its his best tactic, and he used it in the first duel and all TCW duels ta boot.
As we saw in Dooku vs. Anakin 1, force lightning only worked on Jedi who didn't know it was coming. A lightsaber proved an effective defense for both Obi-Wan and Mace Windu when they faced the lightning. With no advantage of surprise Dooku used telekinesis instead, which was enough to disable Obi-Wan.