This may seem like a typical question to some, but it's actually a really good question.
I never thought I would ever look at it that way. I imagined there would never be too many for me. But usually within a month of a new generation being released, I have them all memorized. Not this time though, not even close. Kind of because I'd had other priorities, and I probably will eventually. But I admit, with this Black/White generation, it is a little overwhelming as it is the BIGGEST generation so far, the only one bigger than the first (though not by much), but this really is many to handle at once. The biggest irony of this being the most massive generation is the fact that there are absolutely no ties to old ones, making this generation seem even that much bigger.
So I guess in a way there are too many, but it only seems that way because of how many were released at once. If it were a bit of a lower number, then years later there were more, I wouldn't notice any difference.