Well you can post into the JIRA ticket itself. Note that there are often times different perspectives on what you might think is a bug and what Liferay thinks is a bug. A lot of the time this difference is based upon audience; you will see things as bugs because the code might not be the best implementation for your situation whereas Liferay elects for implementations that will best serve all possible clients from many different business categories.

So be sure to explain yourself in great detail, and if possible provide example code and testing code to show why the proposed solution might not be the best.

Oh, and if you have a better solution, please submit that as well!