Assassins honestly shouldn't depend on kills
Generally when I'm trying to understand the strengths and flaws of a class, I ask myself three questions:
- When do you want to pick a champion from this class? (Or, what's their purpose?)
- How does this class succeed (Or, what do they actually do?)
- How does this class fail (Or, what beats them?)
The problem with assassins, is that their purpose really seems like it should be to take out a heavily defended priority target. However, because of the way assassins have been balanced, that's one of the absolute worst times to pick them.
Right now, assassins are best against teams full of squishies with poor defense - but that's also when divers are best (and generally better than assassins), when burst mages are best, and when Vanguards are best. It doesn't make assassins special.
So right now, the answer to question one is "When the enemy team is full of squishies and I want to play an assassin/a specific assassin is overtuned".
The answer to question two, again, feels like it should be "Carefully picks out a priority target on the enemy team, and neutralizes them or reduces their impact" instead, it's "Tries to snowball early and end before they stop mattering".
Assassins aren't actually great at assassinating, they're good at taking advantage of poor play and at wiping entire teams with a lead. That isn't at all what I think of when ai think assassins.
"Well, what do you think, Boba? How do you let an assassin neutralize a wepl-defended priority target without returning to old Rengar's instant 100-0 from stealth in the middle of 5 people? And what would this mean for assassins as a class?"
So glad to have you here Mr. Strawman! Here are my thoughts:
Assassins shouldn't be balanced around killing enemies. They should be balanced around disabling them. An assassin should function against a one-carry team much the same way Trundle functions against a one-tank team, with the same counterplay of building your team to have more damage threats, and fewer defences. This would allow them to actually counter Juggermaw and "Tristana rolls over everything at 30m comps".
"What would this look like?"
I'm thinking something a beefier than current assassins, while not super tanky, with a natural resistance to displacements and other cc, and powerful, repeatable damage debuffs.
I'll take Talon as an example, because to my mind he's one of the most thematically basic assassins. I won't put numbers, because I know I don't know what would be reasonable:
Passive: Blade's End Talon's abilities wound enemy champions and epic monsters every time they deal damage, lasting 6 seconds and stacking up to 3 times.
Talon's basic attacks against enemies with 3 wounds consumes them, causing them to bleed for (minor damage) and reducing move speed, cast speed, and attack-speed by (x%-y%) for five seconds. Additional attacks and damaging abilities on the target from Talon or his allies extend the duration by 0.5s for a maximum of 5s additional duration
Q: Noxian Diplomacy Virtually unchanged, however, ad ratio is total instead of bonus and the "crit" scales with lethality instead of with crit.
W: Rake: Delay removed again. Ability does double damage to minions and monsters, damage tuned to allow waveclear and provide a damage threat while not being too bursty. Ratio shifted to be total ad instead of bonus.
E: Assassin's Path: This one I'm honestly most uncertain about, but personally I would be happier if it had something like a 15-10s scaling cooldown, no terrain-specific cooldown, and made Talon untargetable while vaulting. Maybe also let him each like Assassin's Creed? I don't know.
R:Shadow Assault: Damage reduced, ratio changed from bonus to total, blah blah blah. While stealthed, Q becomes empowered into a long(er) ranged blink behind target, silencing and blinding them for 2s. Entire R+R+Qblink cannot apply more than 2 stacks of passive.
This is obviously not a fully fleshed out or balanced kit, but the idea is that assassins would have little kill pressure against anyone with decent tank stats, but would be able to duel pure dps by lowering their damage enough to land a couple of rotations, and would be able to dive into teamfights and cripple the enemy's most threatening dps/burst, without killing them.
A fair amount of the damage in their kits would be shifted to debuffs that reduce the damage output of their target (blinds (like Quinn's rather than teemo's), cast time and auto-delays increased, silences that remove all temporary buffs, % attack/spell range reduction, etc). The counterplay, again, would be to not build a team that utterly relies on a single dps champ to be online to succeed - much like the counterplay to trundle.
Other ideas include:
- Lethality giving a % bonus against shields and reducing armor/mr granted by other champions on targeted enemies
- Flat magic pen being changed to do setting similar so that AP assassins can finally have dedicated items
- Powerful displacement-negating tools (thematically the champs could self-snare and hold on to the ground with their claws/knives/swords/daggers/whatever) to ensure target access - peel needs to not be the counterplay or they run into the same issue they currently do.
- Assassins given items that give them durability and a little damage but mostly utility, scaling to lethality/flat magic pen to make them less desirable to divers and tanks.
Anyway, tldr, assassins will never be balanced, feel fair to play against, and be thematically appropriate as long as they're restricted to killing targets to take them out of the fight.