My guess is most small, efficient economy cars aren't going to throw as much heat into the cabin as a larger vehicle. Excessive heat is somewhat wasted energy, until you want to use it. My best personal comparison would be my parents' full size Chevy pickup. All my dad's pickup trucks (past & current) threw heat quickly & windshields are cleared fast.
A little 3-cylinder vehicle is just not going to compete with that. My 1990 Ford Festiva (1.3L, 4-cylinder, 63 hp) threw less heat than my Mirage. I turn my heat down most of the time during the winter months. With my Festiva you wanted more heat. On really cold days, you could expect your side windows to have a frozen layer of ice on them.
I remember surviving in my 1978 Honda Civic (63 hp) during the winter months, but it never threw as much heat as my parents' larger vehicles.
The electric heaters may help the Mirage some? I don't need my A/C to clear my windshield during the winter months, but it does help on humid, rainy days. I really like the manual climate controls on my Mirage. The A/C never comes on unless you push the button for it to come on. I prefer that! Some of my other vehicles would override the A/C button and turn the A/C during certain applications. I prefer to control that myself.
I have never seen automatic climate controls that I would like (in other people's vehicles including my driving school cars) over simple manual controls. I would pay extra for manual climate controls!