Could you ride a larger frame? Definitely yet I don't see this bike as being excessively small.
For a horizontal top tube bike you do have a bit of seatpost exposed yet I don't think its that excessive.
The main difference between your current frame or a larger frame would be the balance between handlebar height and handlebar reach. Your current small frame has a shorter handlebar reach yet a lower handlebar height. A larger frame would nominally give you a longer reach to the handlebars yet a corresponding higher handlebar height.
I'm talking average differences here. Different brands and models have different relationships between heigh and reach built into their frames.