but delaying d4 is not at all harmless. actually meodrn practice of GMs show, they play the italian like a ruy lopez, with d3 , Nbd2-f1-g3 (or Nc3-e2-g3), and then c3 and finally d3-d4.
the fast d4 is often not dangerous:
for instance, 1.e4 e5, 2.Nf3 Nc6, 3.Bc4 Bc5, 4.c3 Nf6, 5.d4 ed, 6.cd Bb4+, 7.Bd2 B:d2+, 8.Nb:d2 d5! with complete equality.
but delaying d4 is not at all harmless. actually meodrn practice of GMs show, they play the italian like a ruy lopez, with d3 , Nbd2-f1-g3 (or Nc3-e2-g3), and then c3 and finally d3-d4.
the fast d4 is often not dangerous:
for instance, 1.e4 e5, 2.Nf3 Nc6, 3.Bc4 Bc5, 4.c3 Nf6, 5.d4 ed, 6.cd Bb4+, 7.Bd2 B:d2+, 8.Nb:d2 d5! with complete equality.