The problem with tanks

So the biggest problem when riot makes tanks is giving them max hp dmg.Tanks shoud'nt have max hp dmg cuz that means they dont need to build dmg in order to do dmg.Ok let's look at an tank that has balanced max hp dmg is zac.He at lv 1 his w only deals 15dmg + 4%-8%(depending on lv) of max hp dmg.That is aoe dmg but it's not rly that high.But when u look at mundo who deals 25% of ur current hp.Yhea it is current hp dmg but...It has a dmg cap so it dose'nt matter if ur at 50 hp he will still do 150 dmg to you.if ur full hp and he q u than if u have no magic resistence items he will deal around 300 dmg.Like what..?The adc deals less dmg than a mundo.Ok now let's look at another problem.Abilities that scale with hp/armor this shoud be removed cuz if u play a tank u shoud'nt be rewarded with dmg for building tank (well maybe exept sunfire cape/Abisal mask).And here are some exemples of taks with too much max hp dmg:Poppy,Shen,Singed(Well u can build him full ap).Giving better base dmg is more balanced than %max hp dmg.Sry for my bad spelling