Daniel,
You are making some pretty blanket and harsh statements. Version 13 is actually quite stable, the 'beta' marking on it is really just a formality as we were going to release it a few weeks before Astricon and then decided to coniniced with Astricon. In the typical form of feature creep we decided to add some navigation aids to it which is going on right now. With all that said, none of that has anything to do with the dialplan and operational aspects of the PBX which go through a more rigourous level of stability evaluation.
There are several thousand systems running 13, and we make our asseesments based on data, not unsubstantiated comments or one off situations. We look at bug rates, the types of bugs coming in, etc. As is normally the case with new releases, there are often more bugs reported that have been bugs for a long time and on earlier releases because of the wave of evaluation that happens on a new release. We often make the judgement call to fix many of these bugs only on the newest release for various reasons. As such, there is often more stability, expecially at the PBX core / dialplan level, on existing functionality.
You state words like upgrading to 13 would be a disaster? So there are thousdands of users out there in a disatorous state? I have a fundamtal issue with such statements without knowing any details of this user's system, what he uses, the environment, etc. It's a very irresponsible statement to make and it comes with no data.
You say I must be joking? So why it is that you "aren't joking" when suggesting someone take a 'blind' set of scripts and firewall rules and plop them on a system?
Thus ... all of this my reason why I ask what 'authority' you have in making such bold statements. I am not making any statements as to what level of knowledge or experience you have, but I am taking exception to your blanket and bold statements that come with no data or no reasoning and are presented in what might come across as pretty 'arrogant' statements. Such suggestions don't provide a lot of value.
As far as your comments on the Firewall, I'm sure Rob was appreciative of anything you shared and looked at it closelfy to take any useful suggestions or comments. It's open source, it can be evlauated very closely by anyone who wants to. And the dynamic elements of it can be easily turned off if one simply wants to take advantage of the ability to add static IP table rules. It will definitely evolve to something even better than it is today, but in the end it is transparent and well documented. It also had the benefit of a development team that is extremely responsive to issues that come up, which is one big advantage over various one off scripts that are out there.
As mentioned, I don't know anything about your specific work, what I do know is how many issues and how much carnage that is regularly cleaned up form random scripts and other things being tossed on systems that people don't understand and very often the original developers didn't really understand. I have not seen any of your direct work (to my knowledge) so in your case, I have not opinion or judgement. I do, as already mentioned, to have concerns about the blanket statements that I mentioned above.