I absolutely love my doorless shower. Cold showers are not a problem for me.
Our bathroom is about 7.5' X 8' and has a wall heater with a blower 4' across from the shower entrance. The heater gets no splash even when two are using the shower (and with two shower heads in each end) and so having the heater there is not a problem. It can be cool coming out of the shower in cold weather. If I remember to turn the heater on, I don't get cold at all when I get out. The opening is only 23" wide so that probably helps keep the shower warm while the water is running.
I'm attaching a view - not sure why my photo is not upright and I don't know how to turn it.
Q