Topics merged.
Number of topics and posts displayed per page have been reduced because earlier values were ridiculously high for global default values and because SMF does not support per-user or per-board values. Meaning these values are used by everyone, including guests. As you know, number of concurrent visitors browsing these forums have been on increase especially since the BtRL release, but first signs are from late last year, probably from the time of the first WCS release.
It just slows down sql queries unnecessarily for having every page refresh to display 50 topics and 25 posts per page. The more people are browsing the forums, the more difference these lower values make. For this reason the values were returned to their SMF default values. Just so you know, values that are generally used in discussion boards for topics and posts per page are typically 15-30.
Now, this does not mean that SMF default values are here to stay. While earlier values were a bit on the high side, we may increase current values to find the sweet spot majority of people will be happy with, but without going overboard like 50 topics per page.
I guessed that the WCS staff will be the first to complain, seeing as they truly have ridiculous amount of sticky topics.

The solution? Create one sticky topic to include links to the important topics and unsticky the rest. You'll find it will make your first page look much cleaner and easier to pick out the updated topics.