Hi
Yes, A corgis ears says a lot - infinitely more than a tail would. Where they 'sit' on a Pem or a Cardi makes a lot of difference to the Corgis head/face and expression.
The American Pembroke Welsh Corgi club on the internet will give you a conprehensive rundown on ears and will quote the standard and you can also look up this one:
www.akc.org/breeds/pembroke