What are your thoughts on abilities/passives taken/based from other champions in champion concepts?

Hey there. I ask this question mainly because it gets hard to make a champion that has a passive which does something specific and keep it balanced/not too OP. This leads to usually looking at similar champions with either similar or same abilities.

For example. Currently I have a champion I'm working on which is all about Armor, Rallying, and pretty much shrugging off damage while keeping the enemy team controlled. In order to do this I wanted part of his armor to count towards his attack damage as well as helping his skills do more damage and such.

The only character that does this (From a passive) is and a champion which has it in his abilities is .

Now, my champions passive converts armor into attack power as well as an innate defense boost that scales with his ultimate. This led to the ability being the exact same as because if I made it too low it'd be useless, and too high it'd be too OP. just happens to have a good medium/balanced passive.

So, when making champion concepts much like that is it ok to use the passive of another champion or should it be different? I know people want uniqueness to the champion concepts and not to be just a ripoff of another champion (Which mine is definitely not because the other skills and abilities are different and unique).

This also makes it hard when creating champions that gain shields, extra AP or AD, armor or magic resist, bleeding and poison, etc. without basing it off of another champion with similar/same abilities to make the champion concept balanced and the best way is to use the numbers that another champion has.

Let me know! Thanks!