Possibly we'll have something like that in the future. For now in 4.3 we have slider constraints which can do similar, though it's different (and more powerful) than most other software.
You can key mesh deformation (any number of meshes!) to store a pose per frame in an animation, then apply those poses using a slider. You can "morph" between adjacent keys in the animation by keying the slider position with interpolation. You can customize the "morph" by using more keys, similar to playing an animation. Since you can key anything in a slider animation, the poses it gives aren't limited to mesh deformation -- you can affect bones or anything else.
We're working on finishing up 4.3 and the documentation. Until then I hope you can figure out how it works without documentation and we are here to answer questions on the forum!
Note that sliders are 1 dimensional. They work great for left/right, up/down, mesh shapes, and many other things. They don't work as well for 2 dimensions, such as left/right AND up/down. Instead you can use mesh weights for one of the directions and a slider for the other. For 2 dimensions we'll have more features in a future version.
