Yes, AD is a very important stat on Illaoi. She is a AD Mage.
The problem i am having with her is that, even though i choose items with HP + AD...i am having trouble surviving without defensive stats.
Even if you see 3 people stacked together you have to:
-Slowly walk towards them
-Press R
-Press W
-Survive for 8 seconds
This is incredible hard...i find myself dying on the part of "slowly walk towards them"
She is very dependant on Flash in teamfights...
Seems like we have to find the perfect balance between AD and Survival stats.