The Phenom 100 has indeed a relatively tall landing gear and a back of the envelope quick calculation suggests 13% static to 26% at 0.4g.
When you design a new aircraft you do so by complying with a set of design constraints such as maximum speed and landing distance. The best design is the one that blends the best design criterias at the lowest weight and cost. Tools exist that can quantify those things with a high level of accuracy.
The landing distance criteria can be met by reducing wing loading (increasing wing area), by increasing lift coefficient (increasing complexity of flap system) or by increasing the performance of the braking system (anti-lock for example).
Or you could add a nose wheel brake.
Now consider the weight and cost of the nose wheel brake and compare that with the weight and cost of increasing wing area a little bit, or going for a slotted flap system.
What design engineers find is that the nose wheel brake is always the heaviest and most expensive solution. So much so that it is a technical solution that is not normaly being looked at during the conceptual design stage.
Where a nosewheel brake may be considered would be as retrofit to an existing aircraft or a badly screwed up design, where there are no simpler solution to reduce landing distance since the wing cannot be modified without going through an extensive (re)certification program.
In short, the nose wheel brake is not the lightest and least expensive path to the design solution, so that path is simply not taken.