Why are there not more champions who have these scalings?
ARMOR, MAGIC RESIST AND HEALTH.
This is a sure fire, guaranteed way to prevent those assassins who can build full tank. By giving defensive scaling abilities on more defensive based champions, or giving certain assassin's with defensive abilities defensive scalings on their escapes or shields. This way they need to pick damage or defense, where going both (or 2 offensive - 4 defensive) is not the best, or even a good option.
Honestly I am not all to sold on the whole skirmishers class being a mesh between carry damage and meatshield tankiness. There is a reason why those two classes are separated. It is because having both is too open from abuse because of the usefulness and minimal downside to going any build (damage, tanky or both) while maintaining an elevated success rate over more static champions.
has
He atleast has one damage item and can kill everyone. If he could do that without the black cleaver more people would be even more salty


and BAM. youre a tank.
But true tanks - much like true supports - are utility based with weak non-standard scalings.