There has been an alternative to the Dock, and it is still available in the new Watch OS. An alternative that I think is better than the Dock was. Complications on watch faces. I use the Modular watch face on which you can have 6 complications. Other people use Infograph for this, which can have 8 complications. Most apps now have complications available. I have different watch faces for different collections of complications. E.G. health apps, weather apps, time-related apps, and apps for communicating.
In the old OS it was just left and right swiping to get to the different watch faces. Super easy. So you could have fast access to more choices than the limit of 10 in the Dock. Unfortunately, it's now a press-hold-swipe-tap to switch watch faces. Annoying, but still a good way to get at commonly used apps. Especially with the Dock now gone.