Walls can just be ignored especially if they don't have cc. tanks need to do some dmg so they can't be ignored and be somewhat focused so yeah tanks need to be able to go for the enemy backline and still be tanky most of the tanks if you go full defense you are ignored if you go 2 items attack you can't tank sh1t and some tanks even with tanky dmg build still don't do enough dmg and get the job done.just go aram and if you get a tank you will see you can't tank more than 2 people or even 2 ppl and you have somewhat equal footing in items. The reason I say this because if you take a non tank champion and you put him 3 mr and 3 pr + hp items he pretty much will do the same work as tanks, "being tanky" that is so what is the point of even having the tank class. Another thing that is not good is that melee champions especially the ones with 0 gapclosers their base speed should be superior to ranged champions for chasing purposes, I know still there items that apply slow,summoners buffs,circumstancial speed buffs in some melee champions,reworks that help with that but still seems ridiculous for melee not having superior base speed.Now some1 will say you want tanks/melee champions to be fast LOL but I will say melee champions without gapclosers have tougher job than anyone plus most ranged champions builds will give them bonus speed so the gap further increases.i can compare it to Lineage 2 daggers were fatser than archers cause if they weren't the would be dead all the time simple :D.
Now I will make a suggestion I will compare nautilus and teemo.Teemo is smaller should be faster/more agile/move his legs faster than nautilus but is he really faster?i mean nautilus is a titan 1 nautilus step is 5 or more teemo steps you see where I am going with this maybe the game should introduce something like acceleration/agility to work in conjuction with size/speed. giving an example nautilus can slowly gain space at teemo in short distances and if he can't immobilize/slow him, teemo instead gains advantage in longer distances and escapes,also teemo has better startup.So smaller champions advantage should be agility/acceleration and attack speed(meaning faster animations those who doesn't require channelling of course) over the big ones, something that you can't say distincts them in early game unless they have boots and you don't but still meh attack speed is also low for these champions early game and you can't say they scale good enough late game cause come on all the attack speed comes from items.of course you take in consideration the nature of every champion but I suggest this as class characteristic. mages shouldn't be fast really cause they are not trained in physical combat,haven't trained their body etc of course things will vary when mages have ethereal forms or float in the air :P. Another thing would be introduction of casting speed for mages and attack speed and ad being irellevant to pure mages so the ap is the dmg the auto attack does but still would have to do changes in items and ap ratios to balance things. ad auto attack on pure mages is stupid really.
Of course in this post I talk about base values and how they scale later in game and how they represent their respective classes and individually objectionally
, you can remove nearly half a tank's armor in one fell swoop
Armor items like 
are shadows of their former selves. Armor Pen was counter-balanced by AS slow. Attack speed by Armor, Health by AD. But crit has no counterpart. And AS slow items have been brutally nerfed on top of it all. And that's before the fact that a tank has to build both MR and Ar, on top of hp to survive.
and 
for atttack speed items and still ad was balanced for armor and health but crit had nothing to hold it in check same as now (
