Question for the Masses

So , I have a question for you all - mainly because my small group of people have been talking about since the arrival of Sett.. and still can fathom in what universe whoever designed him hailed from ..

Back when came out.. he had a scaling shield on his W (for 0.4 of his armor and 0.4 of his MR) - (for those that remember it) and people complained and whined that giving a guy with that much HP a shield was just way to overpowered and it allowed him to basically stand in the middle of fights and bully people for much to long..

Riot heard the squeaky wheels and said yes.. they agree that the shield on a tank was just too strong for that type of character -- also that because the shield scaled with HP it would just to too large to be dealt with..

Now along comes who is a tank - -- who has a shield Ironically on his W - that scales with "grit" and ofc his Grit scales with HP (50% to be precise) , thus making the shield scale with HP - -- then to cap it off.. does 210+25% (+10% per 100 AD) -- as true dmg done the center of a decently wide area if you managed to slow anyone

That is what I do not understand.. if Riot said that having a shield on was "way to strong" when it scaled with 0.8 % of his defensive abilities -- why would they give someone one that scales with roughly 25% of their HP -- and DO true dmg,

just makes no sense to us .. ofc , its Riot so perhaps that is the point