Originally Posted by CatWringer
what really, why do people like lulu so much she sucks. horrid ratios.
Games usually don't last long enough for you to build up the big Rabadon + stacked AP builds you see in SR.
MPen is crucial, because you can expect the entire enemy team to build at least some resist.
Tankyness is important, because you won't always have a tank and a bruiser and a support to protect you.
All those combined mean that good Dom itemisation is very, very different. Late game casters will usually only have 200-300 AP, not 500+. As such, AP ratios aren't really all that important; base damage and utility are more important, and Lulu has both in abundance.
Hell, pure tank supports (Janna, Lulu, Sona) are fairly common; they build no AP at all.