As far as whether CPAN is rendered less useful by a proliferation of modules providing similar functionality... My opinion is that this is a strength not a weakness. Imagine a CPAN where there was no competition for the solution to a particular problem. Would the one module be the best module? Or would it meerly be decent?
In particular, I think you have to ask why there are so many CGI/Templating modules? My answer is simply that this is a hard problem without a really good general solution. For the same reason, why does DBI have almost no competition? Because it is a really good general solution. Maybe someday CGI/Templating will have a DBI and all the rest will disappear, or maybe not. But just saying that having 30+ modules is bad doesn't get us closer. Neither would everyone voting for the current top 5 and acting to prevent a possible DBI-level solution from gaining users.
Update: Whoops! I took this serriously! Looking at your popularity list I see it must have been a joke. "Unicode" is the most poplular module followed by "HTML" and "User"! Hah!
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