@IgorG,
I can more or less remember the introduction of the expanded support of many (new) OS-es and, if I am not mistaken, this was an approach to counter cPanel or DirectAdmin.
However, the issues with Plesk on CentOS are not only limited to Plesk, these issues also occur with cPanel or DirectAdmin.
In a sense, your statement that the number of Plesk/Cent-OS installations is causing more reported issues should be correct, but one should not forget that most of the reported issues are not unique to Plesk, they also occur in other hosting panel installations and/or in the CentOS environment in general.
In our business, we have never used Fedora, FreeBSD and/or CentOS, but relied upon RedHat, Suse and primarily Ubuntu distributions, for the simple reason that the latter distributions are (also) supported by the open source community, with a specific party directing code development and controlling stable releases.
Personally, I can imagine that Parallels chooses to support CentOS, but I also feel that supporting this and other OS-es does create the need to assign a lot of (development) resources to bugfixes for those OS-es, while development should be focused primarily on the evolution of Plesk.
In a certain sense, a paradigm shift in Plesk development has occurred, by supporting the "zoo of OS-es".
And as a result, if we are honest, the support of specific OS-es also has opened up the "zoo of sysadmins" that are using those OS-es, with these sysadmins often not having the knowledge or capacity or resources to administer a hosting panel properly.
The above is often reflected in these forums, in which some questions are asked regarding issues, that (normally) cannot be replicated, unless a number of major mistakes has been made in system set-up and bare server configuration.
I am pretty certain that a vast number of Plesk/CentOS installations is not the primary reason for all those reported issues.
In the best case, it is a secondary or tertiary reason.
In short, the introduction of the integrity checker and/or repair tool could be a starting point to reduce the CentOS related errors, but I assume that it will not suffice.
In essence, I do not understand why sysadmins are not trying a new OS, if an old OS with Plesk fails everytime and they waste days in resolving problems.
Kind regards....