In fairness, yordles are pretty whimsical about their huge mechanized army. The consistent personality theme is "lol let's blow this guy up with our future technology."
The biggest lore issue for yordles is really Teemo. Every yordle is either:
* Technologically advanced (Trist, Corki, Ziggs, etc.)
* An outcast from Bandle City (Lulu, Poppy, Veigar)
And then there's Teemo, who apparently lives side by side with an assault mech and an air force and fights with...a blow gun. What is this guy doing?
(Amumu and Gnar are also problems but only in the sense that they screw up the "yordles are aliens from outer space" theory by being prehistoric.)
Maybe they are...ancient aliens!
But yeah, Amumu's status as a yordle need some updating/comfirmation.
Also, Lulu was kicked out of the yordle city because they didn't like her whimsical magic ... they really should take another crack at this whole lore thing.
To be fair, i'd be freaked out if a little girl came out of nowhere and turned a bunch of kids into flowers and would want her out of my city. That's some Minus shit right there!