Let me start with a confession: I was one of the many Apple Watch naysayers. When the wearable was first announced in 2015, I thought the last thing anyone needed was a screen on their wrist. But now, with news that the company has seen sales rise 54 percent, resulting in around 18 million units being sold last year, it's clear that the Apple Watch is here to stay.

Making matters more impressive is that Apple has now far eclipsed its rivals. As analyst Ben Bajarin suggests, the smartphone company now controls 75 percent of the wearable market, and 90 percent of the smartwatch market. In three years, it's already the world's biggest watch maker by revenue, outselling the entire Swiss watch industry in a quarter.

The question, then: Now that Apple clearly controls the market, what's next for the Apple Watch and wearables in general?

It's a question more complicated than it appears. With other successful products like the smartphone or tablet, companies have had a clear path forward: Add features, refine the design, and increase performance. While that certainly applies to smartwatches and other wearables too, the Apple Watch in particular has had an unusual trajectory. With each release of its Watch software, Apple has significantly changed the mode of interaction, almost as if it's still figuring out not just how to best tune the interface, but how to answer a more fundamental question: What is this device actually for?

After all, Apple's own marketing was initially rather vague on the point. The Apple Watch was their "most personal device ever" — but that's hardly specific. Yet, with the release of the Series 3 Watch with cellular, which let users make calls or receive messages without a phone, things finally came into sharper focus. The Watch was meant to offload simple tasks of consumption, while also being a fitness tracker. In essence: Wearables make smartphones more bearable, in addition to helping you keep tabs on your health.

With that in mind, the path forward for the Watch and the wearables market in general becomes clearer: Augment what they can do as medical devices and, perhaps counter-intuitively, focus the design on constraint rather than merely add features.

One obvious step forward would be to add genuinely helpful health information like measuring blood pressure and blood sugar. The latter would of course be particularly helpful to diabetics who currently have to prick their skin to get a reading. And being able to get a measure of blood pressure over time will be a boon to people as they age, perhaps allowing them to preempt the need for medication.

It's true that health data is not an inherent good. It can lead to fastidious tracking and an obsession with metrics. But thus far with the Watch, Apple has done a reasonably good job of trying to think about health as a daily practice, encouraging users to stand up and move around regularly or meditate with the new Breathe app.

The point of the device is to help focus and guide a person's approach to health. Why not take a similar approach to one of our era's most annoying problems, relentless distraction?

One way to accomplish this would be with a novel design to notifications. Right now, an Apple Watch lets you select which apps can send notifications to the phone, or you can turn them off altogether. But that isn't enough. Take text messages, for example: It is very useful to be instantly notified of a text from your kids or an elderly parent, but far less helpful to get random messages from your telecom company or even a friend with whom one might be texting frequently. The same could obviously be said for email.

To fix this, any wearable manufacturer would have to let users control notifications by contact, rather than by app — that is whom is sending the message, rather than which app they are doing it through.

That level of granular control would allow a wearable to fulfill its function: to act as a filter for a smartphone that can do everything. A well-designed smartwatch interface could deliberately limit notifications and even functionality so that it almost behaves like a barrier, letting someone keep their phone in a pocket or purse but still get the information that is genuinely helpful to them.

This brings us back to answer to that existential question for wearables and particularly smartwatches. Their purpose is to act as an antidote to the tech that has preceded it. And rather than merely tracking steps, or even showing a user their heart rate, a wearable done right will conceive of health in a more holistic manner — letting us keep our smartphones at bay, and as a result, leaving our bodies and minds more fit.