Bear in mind that while previous models can be adapted to the 'power puck' driver system, the Hydra cannot. At this time, there are no plans to make the Hydra upgradeable, so it is basically a stand-alone unit in the AI lineup.
My speculation (and bear in mind that this is merely MY guess, based on trends I've noticed in the industry and the same rumors that anyone attending an industry show will hear) is that the Hydra is just the first of a new generation of AI models. I'm guessing (AGAIN - I am taking a completely uninformed shot in the dark here, I have NO KNOWLEDGE of AI's actual plans or intentions) the Hydra is the model they've chosen to spearhead a new AI controller platform at some point in the future. As lighting units become more evolved and complex, they already contain the precursors to controller language and compatibility... It's not too outrageous to think that the companies involved in their design would be able to generate complex system controllers, as well...
More of my opinion: Up until recently, lighting companies have been sort of at the mercy of the controller companies, required to tailor their fixtures to the protocols that the controller companies developed. Else, they'd find that their expensive, newly-released fixtures wouldn't work on the popular controller, essentially a death-knell to the longevity of the fixture. The lighting companies have begun to work around this stricture, with just such elements as the 'power puck' driver. There is not too far to go from a small driver to a larger, more comprehensive controller...
