In order to cope with the expected increase in traffic demand, the large-scale deployment of Small Cells (SC) becomes a cost-efficient way to realize the foreseen capacity explosion in the near future. In this paper we investigate, for a particular forecast in the 2020, what are the requirements in terms of capacity per area unit and how SC densification along with other design criteria can fulfill such demands. A wide set of illustrative numerical results are provided showing key design criteria such as frequency reuse, deployment planning, macro-cell power-down and transmitted power reduction, which, in conjunction with SC densification, have strong impact on the capacity delivered by the network.