Sucker Punch users are not particularly relevant enough in the metagame as a main reason to use Disable. Additionally, Alakazam doesn't have the typing (an area which Gengar excels in), let alone bulk, to actually use it, since Disable doesn't offer substantial protection or support. If anything, just use a coverage move, Substitute, or support option (with Focus Sash, of course) in that last slot.
Speaking of which, Thunder Wave + Focus Sash is a personal favorite of mind, since Alakazam can't OHKO them all, and paralysis helps immensely against threats with one too many speed boosts, mainly Volcarona and Dragonite (both of which Alakazam can't OHKO usually without the correct Hidden Power). Think of it as a last ditch effort, since no person is bothered to Taunt Alakazam.