I think a complete review and update of BadgeGen would be really welcome.
First There are specific badges which are almost impossible to gain now. For example, what's the use of the "The Ape Cacher" and "The Lost & Found Cacher" these days? Lost & Found caches were a very temporary thing 6 years ago, and impossible to find now. Same thing with "The Ape Cacher": there's only one Ape cache left now, the rest is long long gone. And I still have to encounter the first cacher that has found more than 2 of either of these cache types.
Second, there's several badges where I feel that the counts needed for the next badge is out of balance. For example, 80 FTFs needed for a gemstone, and 300 FTFs to complete the badges? I feel that count is far too hihg and is one of the reasons why there are so many "golddiggers" around. Then STFs and TTF are indeed not valued at all, as others have said already.
Another imbalance is found with the amount of discovered/moved Travel Bugs versus Coins. Just a visit to a geocoin fest will produce the ultimate gemstone for Coins in one go. However, most of the Travel Bugs encountered are not counted because they are not Travel Bug Dog Tags. Farm Tags, Country Tags etc are all ignored.
Then, over time, there are only less and less Virtual Caches and Webcam Caches to be found, as no new ones are created anymore. Since it's harder for new cachers to get anywhere near to the amounts needed for a gemstone badge, I would expect the numbers needed to diminish over time.
But instead, the badges and the counts needed to score them are static. While in real life certain cache types have completely gone or are harder and harder to find. While BadgeGen as is was probably great at the time it was produced, it doesn't necessarily represent the current possibilities in the geocaching landscape.