I can see the issue with having many employees running around in a WordPress install and how it'd be a problem to manage those employees. Without getting into describing the issue overly (it's trust), the three ways to address this are 1) by code, 2) by management, and 3) changing platform.

1. There are places in WordPress that can't be modified by a plugin without forking/reimplementing very large chunks of code to do so. Forking the core code in a plugin is still forking core code, along with all the costs associated with that.
2. "Better hires" is a bit dismissive of the issue. This suggests restructuring the business might be easier then restructuring the software, LOL. If the current business structure does allow for highly paid competent and trust worthy, and this option is cheaper then 1 or 3, it's still a business management decision, not a technical/platform decision.
3. Changing platform to me would include comparing the costs involved with hiring staff to fork core code and maintaining it with the costs of technical support of a different platform. This falls under "best tool for the job" recommendation that you often hear about.

It sounds to me like Mr. Gallagher found 1 too expensive, 2 not an option, and so went with 3 as does happen sometimes. As with most people, Mr. Gallagher prefers WordPress and was frustrated with having to go with another software, and so listed the faults/limitations that made him do it. What's wrong with that?

Cheers