Each finite $p$-group $H$ may be embedded in the Frattini subgroup of an appropriate $p$-group $G$ (for example, $G=H \wr C_p$; here $d(G)\le d(H)+1$. If $G$ is such, then its Frattini subgroup $\Phi(G)$ contains a subgroup which is isomorphic with $H$.)
Problem. Is it true that one can choose $G$ so that $d(G)=2$?
Yakov