Don't rush to judge but I think Rylais stats and cost should be lowered for more obtainability
Lets be real people mainly buy this for the slow and not the excessive ap/bonus health.
It costs way more than other essential ap items especially for mages since the midseason changes.
Items with cdr and mana especially, then there is the anti-get face rekt items like
that also gives cdr and a better build path.
And against 2-3 tanks you will most likely need
/
before any luxury item like 
And then there is all the other niche ap items that take too long to build just for their passives.
I really think these items need easier obtainability(its a word cus I said so) by lowering some of their stats for a lower total cost, allowing those who build it to make use of the passive faster which is the whole reason they want it in the first place, starting with 
Id say something like 100>80 ap, 400>300hp, total cost 3200>2500