Seriously, gunblade is just a better item right now. Even on champs who aren't going to make good use of the ad (which really, it makes lasthitting that much easier on mages,) the only thing you're getting from the wota is 10% cdr. There's much better sources of CDR, and the active on gunblade is actually pretty useful. So where's WotA's niche?
Wota is 900 gold cheaper on top - so you almost can get Wota + Sorc shoes for the same amount of gold which is a big thing - especially for Vlad :) I also prefer it on Mordekasier tbh
Yeah, I'm pretty sure it's mostly cuz it's cheaper most mages dont cs with their AA anyway so they dont need AD the CDR IS useful ;o
idk wat you mean by "better sources" of cdr
cuz i build stuff like...
and only 1 of those items actually give me CDR
Vlad?
sometimes u dont actualy need all of gunblade benefits such as LS, so instead of wasting some extra money on upgrading
to
when u actualy only need ap and spellwamp u buy 
or leave it as to save money for other important items
Why buy WotA?
Wota is 2500 gold for 80 AP and 20% spell vamp. Gunblade is 3400 gold for 80 AP and 20% spell vamp.
There are 2 things alone that really matter for item power:
WotA is easier to build into 20% spell vamp due to being significantly cheaper. WotA offers the same 2 important stats for significantly less gold.
if there was an item that offered 2000 AD but was a 1-major purchase and cost 80,000 gold: it would be the most useless item in the game. You can't just look at the end stats and compare items by slot for slot. Average game only sees 11,000 gold, which is more 3 major 3k items and boots.
Its cheaper and CDR is actually really hard to come by. Most cdr item are either tank or support item
