I still think there’s a good chance we will see the S20 as an option to replace the V6. I also don’t see the Camry going hybrid only.
I think engine options will be:
A25
S20
A25 hybrid
T24 hybrid (TRD/GR only)
Just my $.02.
I don't see S20 happening for a few reasons. It is only ~250hp so, on paper, it has practically no benefit over the high torque A25 hybrid that makes 245hp and will get drastically better fuel efficiency. Plus, that A25 hybrid is already a certified for US market engine. Drop it straight in from a number of already existing vehicles.
The more I think about it, M20 hybrid and A25 (high torque) hybrid should satisfy 95% of Camry buyers. Throw the V6 buyers a bone with the T24 hybrid. That leaves Camry with 200, 245, and 340hp and 50, 45, and 35mpg.
IMO, S20/T24 makes a much better case in a Rav4/Venza than Camry. The Rav, despite moving 400k+ per year, is one of the few in that market that doesn't have an uprated engine. [I'm ignoring the Rav4 Prime since it has such limited volume and the extra power is just a side effect of the PHEV capability]. That said, the same thing as above where the high torque hybrid A25 would give the Rav performance practically equivalent to the T24 or S20.
A lot of my opinion on the T24 being in no man's land comes from the way it is tuned. It doesn't drive like a turbo engine in the Highlander. The engine and transmission are quick to downshift when you ask for any power and the boost comes on smooth with the revs versus feeling that boost surge, so it doesn't feel like a performance / turbo engine. At that point, I'd rather just have the hybrid and the gas mileage benefits if they aren't going to drive drastically different.