Sociology is an academic subject, just not one of the better regarded ones. If you like it a lot more than geography, it might be better to carry it one (no point taking a subject you hate), otherwise, I sometimes get the impression that geography is better thought of. What other subjects are you doing?
It's fine. Take whatever subject you like best.
Sociology is certainly not a 'soft' subject! There are loads of figures and studies to learn, as well as the views of different sociologists. There's a lot of political knowledge mixed in too: new left realism, the new right, marxism, interpretivism, functionalism, feminism....
I've found it to be very enlightening and helpful for doing my English degree starting in October.