User blog comment:Xyclone010/Mastery Discussion/@comment-12904660-20140817172935/@comment-1330314-20140818111537

I used to think the same thing, but when you could have up to 30 different unique effects to keep track of, remembering masteries would risk turning into book-keeping for both you and your opponent (i.e. it'd shift gameplay away from the actual game, and more towards remembering which effect does what in which situation). Some "boring" stat passives are also interesting in their own way, as to get them you have to make a strategic choice in which mastery tree to commit to: Hardiness, the + armor passive, has a huge impact on both laning and jungle survivability, for example, but getting the full bonus requires more than 9 points in the Defense tree, forcing you to trade off either utility or offense to gain access to better defense.