What are the possible consequences of excavating an exterior basement wall?
Knowing very little about your home's design, I can only say that it's unlikely that you'd cause problems by excavating along that wall. Backfill soil is almost never a structural component of a building. In fact, it causes many problems. 

It is possible that you'll encounter drain tile or other utility items that you'll need to deal with. Drain tile that's above the footing would need to be routed elsewhere or left in place.