You know what really grinds my gears???
When people complain about tanks/bruisers/juggernauts dealing damage while building tanky, then turn right around and say that mages/adcs/assassins need more defensive options on their itemization.
news flash: tanks and juggernauts deal damage to squishy targets, and pretty much ONLY squishy targets, because they have high base damage or continuous AoE, and their targets dont build any armor or MR. Or health even. Bruisers deal damage because they build 1-2 offensive items and deal damage around their CDs. Have you ever seen a tank fight another tank? They deal 0 damage to each other.
Meanwhile Adcs and AD assassins have seen a huge increase in damage mitigation and safety while still building damage in the past few seasons. 
are all items that ADs can build to become tankier and avoid damage while not reducing their own. Tack on items that Riot tailored for them in 
and they can become juggernauts in their own right, as seen in the worlds patch.
The hypocrisy must end. To complain that a tank deals too much damage to a champ that is building 0 MR is unfair, yet an ADC can face tank a tank or juggernaut because of lifesteal and hybrid AD items that combine offensive stats with defensive passives. Thats bull shit. I know, you know, Riot knows it, but they love ADs atm, so they do nothing about it.
is a tank shredder, no matter how you slice it, one of the best, in fact. The item was made for Juggs. You can say that it was moreso made to allow Juggs to cope with tanks, but with the amount of regeneration on most of their kits, they're basically a tank's worst nightmare already. These champions need 2-3 champions to focus down, or else need to be kited by ranged CC or damage. That's not to say they can't kill a few squishies in the right circumstances, but the tanks get far outclassed quickly unless they get some extreme damage help, and probably some hold, too.
. I mean, sure there are a couple assassiny ones, like 
, but that's not what a diver is. A diver grabs a target through any means, then simply has more difficulty escaping from battle once he wastes his movement abilities on going for a kill, and has backup stats or power to deal with it. Divers are not assassin class part B.
Divers have a few things in common skarner lacks; some massive mobility ability but his is a weaker speed boost than udyr, high damage combo which he doesn't since his rework, and survivability to shrug off an attacker though again he's flimsy compared to others here.
Divers are just the grey area between bruisers and assassins; just like juggernauts being the intbetween of tanks and bruisers. Your description just makes them sound like an alternate assassin, lol. There's always overlap and it's most noticeable using flexible builds.
