This request is not critical, but it would be good to implement.
To enhance security of software based on Yii it would be great to have a possibility to variate design of some Yii-specific UI elements with several configuration options. It will allow to hide the fact that software is developed with use of Yii. Currently, at least 2 UI elements clearly signal about the fact that Yii was used:
a) default captcha font;
b) default design template of application.
I reviewed many websites and often met situations when these default design elements stay as is in production version of software.