Any competent ham knows full well that the very best accurate source of ham repeaters for
your area would be whomever the local coordination council is. For my area it would be
ARCC's website. There is NO beating the accuracy of the local council.
I'll guess you've only dealt with one coordination group in your time as a "competent ham". I've lived in several states and regions, and have found the coordinators to be only as good as their desire to serve others. For many it's a power trip or exclusive members club, others just like the title. You may want to research the Florida repeater council as an example, and the excrement show it was until overthrown a few years ago.There certainly IS "beating the accuracy of the local council."
No, Sir, the local council is not the accurate data source you proclaim. The much promoted ARRL repeater directory has been famous for years for containing dead pairs (some years old), missing PL or other data. The source for the ARRL directory? The repeater councils. Repeaterbook, too, and they tell you so, loaded the same data as the ARRL directory, as well as data from other sources. Repeaterbook then explains that it's up to us to ensure the data is valid. We in the field are the editors. As KD8DVR pointed out above, notify Repeaterbook of changes or incorrect data, and they edit it. I've had good results with them, and update as often as I can in my travels.
I've found web searching local club sites in areas I travel to as the most up to date source. Many have a published email, and an inquiry there will give you the most accurate information, including repeaters that are uncoordinated for whatever reason. Thus, my comment upthread.