My heater core was leaking so I bypassed it. Beside freezing my a$$ off in the winter will this cause any long term problems or effect cooling

 

Looped or plugged, blocking the path to the heater core will not affect the cooling system's performance. Your heater core is essentially a small radiator, so the cooling capacity is decreased slightly, but if the rest of your cooling system is in good shape there is no need to worry.

I have to loop mine because one of the copper inlet tube is slightly bent causing a slow drip/leak.

Replacing the heater core takes little mechanical skill, but a lot of time, as it requires removal of the dash.