|XP is just a number|
some additions. The company Percona* (www.percona.com) does provide some MySQL related tools which can also be used against a non-percona MySQL server. These tools are bundled under the name "Percona Toolkit for MySQL".
How does this fit here? This toolkit is written in perl, it's open source and provided with a GNU v2 license.
One script of that is pt-query-digest which aggregates informations from the slow query log. In newer MySQL versions you can even log every statement, so that you get an overview over all statements over time. As far as I know the script or a companion script gives advice how to improve the statements found.
Probably worth a try. (@Voronich: Something for you?)
* That is no advertisment from my side