Is lethality flawed in the same manner as Last Whisper use to be?

Last Whisper use to reduce total armor by 35%(season 3 to patch 5.21) or 40%(season 1 and 2)

In turn there was no situation where it was a bad item to buy.

Riot then changed it in 5.22 to make it only apply to bonus armor and upped the % bonus armor penetration to 45% on the items it builds into so it would be an anti tank item instead of an all around good against everyone item and also made it build into LDR and MR.

So doing the dangerous thing and applying riots logic for one change to a item to another that applies to the same enemy stat but in a different way...

Lethality is not situationally more effective. It is applied last meaning that 50 lethality ignores 50 armor from a squishy who has only 60 armor total and this is the intended target for lethality builders. It is however also fully effective in reducing 50 armor after BC and LW have reduced 200 armor down to a far more manageable 108.5 already. There is no situation where it is less effective to take Lethality items since the flat reduction is applied last.

Nerfing the numbers might be a "fix" but it is the kind of fix that makes it nonviable instead of making it situationally good against some enemies and less effective agaisnt others.

In it's current state applying after % bonus armor pen it is one of those things where if it is too strong it is oppressive and if it is too weak it is completely ignored. There is no way to effectively build to counter it and that might be the core problem with lethality.