Robin,
Just wanted to say do not get discouraged with the profiling and review process. I can speak from personal experience that it will become clearer with every card you submit. I like others here, learned through trial and error. The writing may come to, I wasn't one for writing, my first cards were blank but after a while I tried a few lines in some cards. It helps to check out your local card store to put you in the mindset, if you read enough of them your whole day becomes a greeting card line!
 
Other things that may be helpful, when you are choosing a category for your card go to that category and look at the other cards there. Would yours specifically fit in or be a 'could apply', or search on your subject/ category and see what cards come up and see what categories they are in.
As far as the reviewers I have personally found them to be most helpful, they have to keep things specific to categories or a customer will just be lost in a sea of could be's looking for a specific card. I never take any comments personally.You can always send an email to the review team in response to a returned card that was not accepted. Turn any resubmits into an opportunity to learn and you can end up with a better product.
You are off to a great start, you just have to get over those few bumps in the road first.
Pamela