The Summoner and Single Player Sessions

Seems to me like the Summoner (and to a lesser extent the Beastheart) might be a lot of fun for a PC in a duet style game.

I’m curious about opinions/experience on how different classes interact with Duet style play. Like could a Tactician work at all? Is a Censor disadvantaged because generally they’re more focused on locking down a single target? Is the Void Elementalist no longer the best subclass?