I’ve gotten it too. I don’t think it matters much if you use Anki on your computer. If you have some decks which you can merge together, it’ll be a good idea to dou it to avoid Anki getting slow (but I think it’s mainly on devices like phones). If you can avoid making too many mew decks, then avoid making too many new decks. I know it can be difficult with textfugu, as textfugu regularly tells you to add new decks.
I’ve just added the last kanji and vocabs from season 5 and I still don’t have any problems with a slow anki.