no one is perfect, and the swaps are open to all skill levels, i think it is very sad that anyone would participate in a block swap and then complain to the hostess about blocks not as perfect as they think they should be...how rude! ranks right up there with complaining that you used walmart fabric instead of quilt shop fabric.
you should do your best and use the best quality fabric you can afford and
THAT SHOULD BE ENOUGH! if you are happy with the block i think you should use it.