I mentioned that removing asterisk-11 rpm might lead to some base config files (queues.conf, or some other not _additional.conf files) be overwritten, so restoring the ones from issabelPBX (or reinstall issabelPBX) will fix the issue.. it won't "brick" your system, but you might end with a partial working asterisk. You can restore backups, or you can reinstall issabelPBX or copy those .conf file manually. As limits, the software itself does not impose any limits, perhaps you will need to increase stack sizes, open files, etc.. There is a problem / limit with asterisk macros, and issabelPBX relies heavily on them.. but the problem becomes aparent only if your dialplan is kind of "recursive" so to speak, making a call go rounds in your dialplan will hit limits. Newer asterisk versions are deprecating macros altogheter for this reason, in the future we might modify the diaplan and replace macros with functions.
Best regards,