Well I don't think it's a dumb idea.

Obviously.
We have a lens review section, but it's not as active as the lens forum. And people have a propensity to name their threads in non-descriptive ways like "look what I just bought" or "
LBA strikes again", which doesn't tell much about the content of the thread.
Or, as in the tripod collar thread, contains extraneous, yet interesting or valid information about a specific lens' attributes and performance that isn't hinted at in the headline.
I like the "club" threads because they concentrate specific lens topics into a thread that will immediately tell you what to find inside.
Which is basically an extended lens review that promotes a more nuanced discussion besides what you might find in the review section like "I just paid a bunch of money for this lens and that's probably why I think it's at least 8.5 out of 10" or "this lens sux 5/10".
I'll agree with the other poster and say that perhaps it's better to have a "star*" club instead. . . .but on balance, I prefer targeted threads.
my 2 cents.
I'd like to see more 'club' threads. Lenses that don't have a large user base will dither into obscurity -- but lenses that have a dedicated user base will thrive. And if you're looking for information about a particular lens, how it's used, and what people are doing with it, the specific threads are very pleasant to browse.