Why not nerf/buff more champions but only a tiny bit?

So Riot,

I love League but also played Dota for a while, and one thing I noticed is that they tend to nerf/buff way more but with less impact. So i am wondering why you dont make more small changes to champions like u did with , even tho people kinda laughed at that change, i feel like that is a good way to nerf and buff champions. Same with , only some small changes can bring champions that little extra/less they need to be a blanced champion. Just wanting to know if there is any philosophie behind it or you just think that big changes are a better way to go. This applies to the new item changes as well, couldn´t u just decrease the extra crit dmg for ranged champions by like 25% to nerf it?

Thanks for reading

Ps: I believe the mundo buffs were nice.