This particular bit of news has been confirmed by SCEA marketing exec John Koller, who mentioned that PlayStation Now titles which are streamed to mobile devices will “need to go through the DualShock”, and as at press time, alternative touch-based methods will not be on the cards. Koller shared, “The DualShock remains the key ingredient. So that controller experience needs to go perfectly. We didn’t want to utilise touch screen or anything like that because the games are best played with a DualShock. It requires the DualShock. The DualShock 3 specifically. To enable tablet and smartphone play, you’ve got to have the DualShock 3.”
Do bear in mind that a DualShock 3 is not a requirement for PS Now gameplay to happen on the PS4, as that is where the DualShock 4 comes in handy.