If someone is making a league forum, it makes sense to have all the teams to be in a separate forum. However, I would still argue that, in this case, and just starting, "AFL Teams" should be 1 forum and that the 20 teams should be prefixes instead. When there are 100~ discussions on each team, simply branch out and create individual forums for them so that they can go into sub-topics for the teams a bit more with better prefixes for team-specific discussions. It wouldn't be that hard to organize/move the threads at that point because you could search by prefix/select all/move into the new forum.
And that's my argument why if you use XF, having individual forums, with many possibly empty is foolish.
And it is not necessary with XF. That's the beauty of the prefix setup that it uses. You can click on any of those prefixes and the only posts you see are those using that prefix.
It does require mandatory prefix use in those areas though as many users may not utilize them unless forced to.
Now, with other scripts, they may not have that ability, so individual forums or forced tags may be the only options.
But according to her it was "better" to have all these as separate forums. I don't think she realized exactly how many prefixes were in use as she apparently only has exposure to a maximum of 12-15 needed, and for that you could probably get by with individual forums.
And these are just a few of the prefixes for that area (Telescopes & Accessories).
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For anyone counting, that's 35+ with a few not shown in those images that would be a forum. Just browsing them would be lengthy.
Now, let's consider the Software & Computer hardware area
There would be another 23 forum nodes listed. So now we are up near 60 forum nodes and we still have SEVERAL other niche topics to cover. If each prefix was a forum node, I would need around 120'ish nodes.
But it's easy enough to find and filter the one you want using prefixes in one master node. So really, no need to "branch out into individual forums" if you think about the prefix structure and lay it out well.
What it told me quickly was that she had no clue what she was talking about - which was not that abnormal for her to be honest.