Walking on Air and Legendary Lovers should have been the 4th and 5th single, not birthday and TIHWD. Idk what she, the label and her team were thinking

Then, she would close the era with a nice ballad. Never mind, we are looking in the future right now. Katy should promote something new at this week of SB, Grammys. A collaboration, a new single or a new lead single would be perfect. I'm sure she has written a lot of songs or she can still get back to studio and write another 2-4 songs for the re release. The other option is to make a collaboration. The third option is to promote the last single off PRISM in that period.