What is Riot's current stance on items that supply both defense and AD?

I seem to remember that 2-3 years ago, the item Atma's Impaler was nerfed. It had the following stats:

Atma's Impaler

• 45 Armor
• 18% Crit Chance
• Bonus AD equal to 2% of max health

It was built on every bruiser as part of the meta golem build. The nerf lowered the bonus AD from 2% to 1.5%.

The rationale for the nerf as I recall (correct me please if I'm wrong) was that Riot did not like an item that provided both defense and offense, because they were too well rounded that it shoved out item diversity.

Fast forward to today, and we see the new Black Cleaver being released:

Black Cleaver

• 400 Health
• 40 AD
• 20% CDR
• 6% armor reduction on physical damage (max 6 stacks)
• Bonus 20 MS on hit

This seems very much in line with the original Atma's Impaler. Some people may instinctively point out that Atma's Impaler had a potential infinite scaling with its passive; however, in practice this was never the case because health ranged between 1500-4000. In terms of slot efficiency, the offensive potential of having 80 AD (only at full build) vs. 40 AD + % armor reduction still favors Black Cleaver, even over the crit chance. If anything, the Black Cleaver reducing armor makes counter-building it more difficult. The key point here is slot efficiency.

The bonus health will actually end up being superior to the armor, especially after armor pen effects. It also boosts survivability against Magic and flat True Damage.

The % CDR has universal utility in amplifying offense, defense, and CC. Along with the Rage effect, this helps the item cater to a broad range of classes; it seems to feature that same well-rounded applicability as Atma's that can overshadow items with a specialized design.

##Question

I understand philosophies change over the years, and also the game is definitely different now than in 2012. Why is this iteration of a defense + AD item better than previously? How does Riot envision its role in today's meta?

Because the meta has changed, this isn't meant to flag Riot as inconsistent. It's about game design philosophy, so please keeping any discussion constructive and focused on understanding the change would be appreciated.