Hi Michal,
Great to know that worked for you! Applying other filters (other than the path filter) via the URL to the console is not currently supported. Regarding your suggestions (that and otherwise) - probably the most straightforward approach to requesting features and improvements is to go through either AEM SoCo's Product Manager here at Adobe or possibly your sales channel/rep - accepted features/improvements will either end up on the AEM/SoCo feature roadmap and/or need to be requested for a special AEM Feature Pack. I will loop in SoCo's Product Manager to this thread to comment on that process.
Also, you are in the right place to ask support questions in the future.
WRT your specific question - "what is the best practice to extend moderation panel with some extra metadata from additional field in comments"
As far as I know (I will let you know if I find out otherwise) - AEM does not officially support extending the administration consoles (such as community moderation) because of the potential of future installations of official AEM upgrades to the platform stomping on or making your extensions unusable.
As such, there is a way to do what you wish - it will require some amount of coding of course. I will put together some instructions and reply to you here by end of the day Monday on how to accomplish displaying additional JCR node properties on comments within the community moderation card items.
Hope that helps! Talk to you soon.
Thanks,
Ryan Wilkes