I'll give the plans to pare things down a double thumbs-up! I've been working on a...well, something secret...that involves putting all modules of a single maker in a rack, and I'm always running into situations where I see the same module posted with slight changes yet it's still the same thing. Sometimes there's a valid difference in appearance (different panel color...I know some builders get picky about their system's aesthetic, and I've no quarrel with that as looking snazzy is a thing, especially when performing), but there's also plenty of times where the same, exact module gets reposted, and that's definitely going to waste database space plus muddle up some of the stats on module usage, etc.
But as for wholesale purging...it strikes me as a little troublesome, as the potential for breaking racks would be significant. Merging of some sort would be better, but in the process would it be possible for the duplicates (which people may have used in builds) to be hidden and kept as 'placeholders' in the event they've been used, while still programming these database objects to point back at the actual, retained database entry? Yeah, that's a lot more programming and seems rather involved, but to my reckoning it could be done in such a way as to seem seamless for the vast majority of users. As far as simple appearance differences are concerned, though, I would very much advocate for some sort of statistical merge, since there shouldn't be any difference in the 'guts' behind a panel, ergo users with different color panels on the same module should have their use counted as being just that module for the purpose of usage stats. F'rinstance, there's several appearance-different versions of MakeNoise's MATHS, including one panel by Greyscale...I think that, irrespective of which panel is used by builders, it should all still count as usage of a single instance of MATHS for the purpose of the stats.
Again, more coding headaches, sure...but it's sorta what comes with having become 'authoritative', so it's definitely not a negative. Just what happens when you turn into the 'definitive reference'.