In many of the forums here, something like half the first page is pinned topics. It really cuts into how easy it is to follow conversations, and probably jacks up your server load since more people need to click through to the second page to find threads they are active in; two page loads per forum is twice the load, eh?
Is there any reason there's can't just be one locked & pinned topic per forum with one post in it that is mod-edited to contain descriptions and links for all the topics that would otherwise be individually pinned? Yeah, its a little bit of extra work for the mods... but less for all users and the server.