No one builds this items. Its outdated and weird as it gives no actual AP. There was a time when ADCs used it but riot quickly shut that down because they got access to much MR.
The item has less than a 1% pick rate and historically, one can say this item will eventually get deleted.
If you want to see a rework that would save this item, please upvote.
thanks
Killer of Night91 votesThis item has a lot of issue.
The principal issue with wits end is that it has a ramp up mechanix.
In the actual meta, all the champs deal burst and oneshot damage instead of sustained dmg.
As defensive item 
outclass a lot 
because it actual provide an anti burst mechanix while giving true Ad (since all the champs that should build it has a good ad scale like yi and udyr and if they want damage while being tank, maw require less action and provide at the same time good stat and two powerful passive.
Getting a full stacked of wits end is at the same time impossible (since the enemy is alredy dead) or not necessary (because Ad damage outscale really hard this item).
Another wit's end issue is 
.
Before the rework, a true on hit build make sense 
< tipical build.
After the rework, it become More stat for get More stat, so a true AD or Ap item would be better than a on hit item (with the nashor exception).
The final issue is the absence of tank.
Since this item as a mr reduction option, it would be a teamfight support item but tanks are alredy melted by the actual purchased of this item (Yi udyr shyvana xin'zhao and other Aa oriented) so it doesn't make sense to get this item.
