The distinction between an overly simplistic design and a minimalist design is an important one. Simple designs should be avoided, as they tend toward being overused, overdone, and not at all memorable. Minimalist designs, on the other hand, are popular for good reason. They are eye-catching, memorable, and timeless, but still function as creative pieces.
The minimalism trend grounds most of the other current trends, which are increasingly focused on sleek, tight designs. Ornate, overworked design has been replaced with cleaner, modern concepts that retain simplicity without forgoing originality.
But tattoos can be great when simple and when complex. It simply depends on whether you want to tell a story, where more complex tattoos can be more effective, or make a point, where simplicity is often better