I am facing a similar dilemma. I actually sold my old CPO Model S last May and we have been making do as a one car family since then. Fun fact: I sold my Model S to Carvana - just plugged in that same VIN yesterday and the current offer would be HALF what they paid me in November - score one for me.
Anyway, when the prices dropped on the Y I ordered last week...delivery date is between 01/29 and 02/12. I also qualify for the rebate. However, I hate the thought of "just missing" a potentially significant upgrade with the HD radar and potentially HW 4.0. I won't be getting FSD, but honestly the elimination of the darn parking sensors really irks me. I mean we use those dang things every time we pull into the garage (and more) AND I can easily see the whole "Tesla Vision" situation (particularly with the current cameras and no radar) being a marginal replacement for true parking sensors...much like cameras are a poor replacement for a rain sensor, and the lack of radar appears to result in more phantom braking, etc. If it were JUST FSD or maybe even JUST AUTOPILOT, I might not care, but the parking sensors get used a LOT.
Heck, when I got that old 2013 Model S I referenced, I held out for an "August" build since that's when they introduced parking sensors for the S!
Darn you first world problems!