My advise is go for Prius 1800cc 3rd Gen 2012-2013 Model, As it wouldn't be downgrade from your current Corolla you own.
the Aqua Rear leg space is lesser.. You won't have that issue in Prius, The dashboard of Prius better than Aqua.
Prius have trunk, can be useful anytime later..
Prius giving avg of 19km/l on rush hour at Chundrigar Road & Shahra-e-Faisal... Avg depends on your driving condition. Normally I switch to ECO mode in traffic jam and sometime Road is empty and not in mood to go in speed.. Other than that Normal Mode.. and PWR Mode on Highway.... on Highway I'm getting 25km/l
JDM car will have issue of ground clearance as well as suspension, because they're made according to Japanese Road.
Ground clearance issue can be resolve by spacer/big tyre.
While suspension is not the best, but then Hybrid is saving u lot in fuel bills, fraction of fuel bill you saved will cover your suspension bill.
I know what you mean by Corolla Suspension, when ever i go through any rough, patchy, bumpy road other than Corolla, I think in my mind if Corolla would have pass through these roads, It would have been comfortable drive over bad road.
P.S Personal Experience and I have owned 1.6 Altis A/t (Current shape) and Prius S 1800cc.